Q There is a lot of emphasis now a days on 100% sampling (all containers ) . Is i t necessary to do identification tests for each drum / bag of raw material ? This could pose a problem in storage of materials procured for long term use, expecially i f the material is deleterious.

A Currently, the recommendation, is that every container of an active material and certain crit ical excipients should be tested container wise. The logic behind the requirement is, that many users have found, variations in quality parameters from container to container due to either inadequate uniformity in the lot material or, due to exposures to temperature and humidity changes during transportation. Sometimes, a shipment of raw material received has a number of containers, which represent an inventory for use over a period of 3 to 6 months, especially in the case of improved materials.

Some materials are very susceptible to moisture and therefore, once the original container is opened, i t must be used as soon as possible. In such cases, i t is suggested that, a l imited number of containers should be sampled as a sublot. Based on the test results, the lot would be either accepted or rejected.

Further, the remaining for would, from time to t ime, be divided into sublots and tested, depending upon the usage plans. In the event of a lot being accepted, and the goods paid for, but, if subsequently a container does not meet specifications, i t should be returnable to the suppliers.

Q Is i t advisable with reference to GLP, to have different sampling schedules for active and inactive raw materials ?

A Both, active materials and excipients have to be sampled according to the same sampling plan, 1 + n containers. Active materials would need additional sampling to ensure quality compliance.

Written SOPs for sampling plans and procedures are required for cGMP compliance. Dr. S.N. Lyer’s previous answer explains briefly, how sampling of active and inactive excipients may be done.

Q Why should sampling be done on bulk as well as f inished products ?

A The bulk product samples drawn from different dosage forms could have some limitations on the sample uniformity. For example, the bulk product is tested and released for packaging. But, because of change in requirements or other considerations, remains unpacked for long periods of t ime, or, in situations when part of a bulk lot is packaged at one t ime and the remaining, after some time, deviations could occur. I t would be appreciated that bulk product storage conditions do not replicate that of a f inished batch. Therefore i t is desirable that the f inished product batch also be tested to i ts release for sale.

Q If the expiry date of raw material is 5 years and i t is used in the last month before expiry for manufacturing the product, what should be the expiry of f inished product ?

A This question has been raised from time to t ime in various forums. The expiry date to be given on the product depends on the stability data that the manufacturer has of the product. In the event of the raw material being used in the formulation nearing i ts expiry date, the assignment of expiry date would depend on the stabili ty data the company has, of experimental batches made under identical conditions. The drug and cosmetic rules provide, that the licensing authority may accept any expiry date, so long as it is supported by stability data. I t may also be noted, that if a raw material carries a 5 year expiry date, i ts formulated dosage form need not necessarily have a 5 year life.

Q Is there any sampling device, other than rods and scoops which can collect samples from different depths of the container ?

A A thief sampler, which is a hollow cylinder cut into half and provided with a pointed end could be used. Still better, is two hollow cylinders, one f it t ing into the other. An opening is provided in each of these at the same depth. A tapered end is provided. The cylinders are inserted into the bag / drum upto the desired depth. Making sure the openings of the inner cylinder are diagonally opposite to

that the outer cylinder. After the device is inserted to the desired depth, the inner cylinder is rotated by 180, so that the two openings are adjacent each other.A slight left to right movement of the device will draw the powder into the inner cylinder, which is then rotated again by 180 and the device is pulled out. This way, the samples from different depths can be collected.

Please elaborate on the retest period for active excipients ?

A Normally, the retest date should not be more than a year for anything. For i tems having volatile components, for example, f lavours, a retest period of 6 months is recommended.

In the faculty’s opinion it will be very poor inventory management, if there is need to retest any material more than once, although, this is permissible within the full shelf l ife of the substance.

Proper planning of production will aid procurement procedures and avoid retesting.

Q For every market complaint received, is i t necessary for the manufacturer to do the analysis of product from a very limited retained sample ?

A No, i t is not essential that the retained sample be fully analyzed or even partly analysed for every market complaint received. For example, if the complaint refers to shortage, empty pockets, broken bottles, the potency analysis of the product is not going to tell us anything about the complaint. Hence, what investigation, if any, is required depends on the nature of the complaint.

Q In the current scenario of IT/ Kanban, reduction in quality inspection and quality at source, is currently practised, especially by Engineering Industries. How much of this is applicable to Pharma Industry ? How can we implement these at minimum cost ?

A JIT or Just In Time inventory management is a very laudable objective to have. However, the current scenario, especially for Pharmaceutical Industries, where several raw

materials are imported and others are obtained not necessarily from one vendor on a need basis, this is not practical. If the company has a selected, reliable vendor who can give assured quality at the specified t ime, JIT can be instituted.

Q What are the pre entry cleaning guidelines for various types of packings HDPE bags, f ibre drums, jute bags, Cardboard boxes ?

A Pre entry cleaning procedures for various materials received in the warehouse, should have cleaning techniques appropriate to the type / constitution of the outer container, the surface of which is to be cleaned. The level of cleanlines required, has to be determined by the company depending on the nature of raw material, outer container pack and the handling conditions in the dispensing area. A system for validating such cleaning would be desirable.

Q What is the retests period of raw materials which has microbiological testing in the specification ? How many times should this material be tested ?

A The retest period for a raw material is usually assigned on the basis of either experience gained within a company six months or one year being the norm or sometimes the expiry date of material is specified by the manufacturer. The objective of retest is to ensure that during storage, the material has not undergone any change in i ts properties. Those materials requiring microbiological testing, should be tested for microbial content along with other parameters. However, in the event of raw materials showing a microbial contamination of increased CFU, i t would be desirable to test stored material at relatively shorter frequencies, than that meant for chemical retests. This is just to make sure that the microbial population is not increasing.

Q Why do granules sometimes get hardened during the granulation process ?

A Many factors influence granulation, some of the common cases for formation of hard granules are :

* The wrong choice of a binder, such as binders with high adhesive property.

* High binder concentration.

* Use of excessive granulating fluid or over wetting of the powder.

* When the end-point of granulation is not properly ascertained.

* Use of water as a binder.

The bulk density of material used in formulation varies from supplier to supplier and hence, the quantity of water added also changes, leading to the formation of hard granules.

Q Batch numbering and code numbering systems vary from one company to another, as they are designed in house. Can you recommend, from experience, a system that you consider the best ?

A There is really no system which can be considered the best. A system must serve you well at the t ime you use it , and it must be constantly reviewed to see if the purpose i ts being achieved. In my experience, the easiest method of batch numbering is the straight forward serial number system for each product. Complex systems including alpha prefixes and extra numberals to know the product identity, year and month of manufacture etc. Serve no purpose, because, all this information has to be provided on the labels in any case, as per regulatory requirements and there is no point in complicating the batch numbering system.

Code numbering of printed packing, materials is a different proposition and there are advantages in coding. Here, I would recommend an alphanumberic system, built around a unique code number for each product, with suitable prefixes and suffixes to identify the packing material and label copy. For example, a label for a product with an assigned code number say 345 could be coded as L 345 Al where L would indicate that i t is a label and A1 would refer to the

specific and current printed copy matter on the label. If this matter were to be amended the code would be changed to L 345 A2. Likewise, if the pack for the same product were to contain a printed carton, i t could be coded as C345-B1 and with any changes. In copy it could change to C345-B2 and so on.

Q Sampling plan for packaging materials - should i t be as per ISI standards, or can i t be changed on the basis of the vendor ?

A Sampling plans as laid down in the ISI standards may be followed, if the vendors are prepared to work out the AQLs with the buyers. In the absence, an agreement i t will have to be on the basis of what the vendor is prepared to accept.

Q Microbial l imit test for FP is not mandatory as per IP Schedule M mentions that all pharmaceutical preparations should be free from pathogens. Are all batches of FP to be tested, for the absence of pathogens ?

Should this test be used as a release criterion or, is monitoring enough ? Also, should a total microbiol cannot be done on FP ?

A It is essential that all non-sterile preparations be subjected to controls for microbial contamination. For this purpose, the source and nature of contamination of all the products should be ascertained by routine monitoring of both, the input mateials and the products, as well as, the environment. In which the products are manufactured. I t is only after this has been done, that microbial l imits can be formulated and then enforced, either as release l imits or, as monitoring cri teria. The WHO has recommended limits for various types of materials and products Reference may be made to them for guidance.

All questions so far have been answered by R.S. layer, Senior Faulty. The Academy.

Q Please suggest what type of LAF workstation should be used where basic f i l l ing / stoppering and sealing operations are carried out for sterile products.

A Vertical Downflow Airflow Unit is generally the recommended LAF work station for the operation.

Q Which is the most suitable validation technique for autoclaves and dry heat sterilizers , Chemical Indicators or Biological Indicators.

A Firstly, temperature is not the parameter that needs verification.

Chemical indicators are normally melting pellets, color change str ips or witness tubes. They measure steam penetration only and not the quality of steam i .e. Dry Saturated Steam. They exonerate the vacuum cycle.

Biological Indicators make use of thermo resistant bacilli . These indicators, besides measuring steam generation, also show the enthalpy transfer to the bacilli and give an indication of the temperature hold. TME as an integrated event. Strips of B. Stearothermophilus spores are used as the challenge indicator when moist heat is used.

In dry heat sterilization, spores of B. Subtilis sub species niger is the preferred indicator.

Here is a quote from the Encyclopedia of Pharmaceutical Technology Page 27, Vol 2. ( Swarbrick and James C Boylan ).

Two primary uses for B1 are validation and monitoring of sterilization procedures. In validation. Bls are used to ensure that a particular carefully controlled process will produce a sterile product under conditions of maximum challenge ( i .e. worst - case conditions ). In monitoring, Bls are used to ensure that this process remains capable of producing sterile products, even under worst case conditions. The advantage of Bls and an attr ibute that cannot be duplicated by any physical measurement is the abili ty to integrate the lethal effect of sterilization agents under conditions in which at least two parameters are being varied at the same t ime. This makes the determination of the effectiveness of the sterilization processes, so that validation can be carried out as well as continuous

monitoring. The more information can be found in the Academy’s Update on the subject.

Q What is the ideal gap required between fi l led volume and the space above the l iquid upto the constriction of the body of the ampoule ?

A Ampoules would most probably be terminally sterilized by moist heat after f il l ing. During this process the temperature rises from 20 C to 121 C . This would mean an increase of the l iquid volume by 6% and so a minimum head allowance of 6% should be maintained.

In the case of vials, compresion of head space air ( or nitrogen ) should not displace the neck of the stopper within the throat of the vial to an extent, that the stopper pops out. The seal force must not be overcome by the compressed force.

Q What would be the method of validation of an autoclave size 4’ x 4’ x 6’ with load of 515 ml. At 15 psi, 121 C for 20 minutes to avoid pocketing of steam in the chamber, Please suggest the ideal validation method and how frequently i t should be done?

A An autoclave that uses direct entry steam as the sterilizing agent, will always have the problem of pocketing of steam in the chamber. The answer l ies in whether the autoclave has a purge system or not ? The purge system does not guarantee the absence of pockets, but definitely voids pockets sufficiently to dramatically reduce the Cold slots. Validation can be done by either the 12 probe method or by the Bacteriological method, but i t can be established only after the process cycles are understood. Today’s technology makes use of super heated water as the sterilizing agent to avoid the problem of steam pocketing.

Q Why should unlubricated granules not be kept in drums similar to lubricated granules ?

A Unlubricated granules should not be stored in similar containers to avoid the mixups between unlubricated granules and lubricated granules. Even the labels used should be of

a different color to facilitate easy identif ication by even the i l l i terate workers.

Q If a drug is non- pharmacopial, how do we select the dissolution conditions media composition agitation ( rpm ) and USP apparatus I or II for dispersible tablets ?

A If the drug is non pharmacopial, the medium selected should be water N/10 HCl or a suitable buffer upto pH 7 USP Type 11 apparatus should be used and agitation should be 100 rpm.

Q What should be the correct head space in a LVP bottle ?How much more than 6% by volume ?

A About twice, 10 to 20% The insights dont’s end there. Full up. Bottle volumes is usually 20% over labelled dose.

At 121 C, a bottle f il led at say, 20 C wet bulb room temperature, has two internal pressures.

1 Partial vapoure pressure which changes from 0.025 to 0.050 bar, and.

2 Partial air pressure which rises from 0.988 to 1.330 bars (applying perfect gas laws to air ) .

The total pressure of 1.38 bars means, that the stopper is pushed at about 1.4 kgs per sq. Cm.

Standard bottles used in our country, 250 ml and up, have a neck of 22.5 mm. That is a force of 5.5 kgs exerted the explusion thrust. Residual stopper sealing force is always of concern and to be kept in mind when adjusting head space.

Q Why is steam, with all i ts associated problems used for steril ization ? Why not super heated water, as is used for stopper ?

A The answer to this, has to do with specific enthalpy. At 121 C, water is at 500 Kilos joules per kg. Associated with steam, i ts at 2530 Kj per kg. And, evaporation enthalpy is at 2022 Kj. This accounts for the large heat

transfer capacity of steam and its abil ity to penetrate the load mass gett ing to where the bacteria are resident.

With stopper, the position is that steam should not be allowed to penetrate as i t destabilises the interstit ial, intercrevical matrix of the closures. Also these elastomers vulcanizites are prone to regression by the action of steam. So it is prudent to use high temperature water for closure sterilization.

Q What is superheated steam and what are i ts l imitations when used in an autoclave ?

A It is important that a critical balance of pressure and temperature be maintained in an autoclave, to ensure a contineous supply of dry saturated steam. If the temperature rises or the pressure drops, the degree of saturation is reduced and the steam becomes superheated.

The objection to super heated steam is technical, enthalpy transfer. Superheated steam inhibits the transfer of moisture as i t condenses less readily than dry saturated steam. Due to decreased condensate levels, the moisture required to init iate cell destruction is just not available. The cite just one value here the specific volume of steam at 126 C is 0.743 m3 / Kg and at 121 C is 0.841 m3 / Kg nearly 13% less at the higher temperature.

Q What happens to the F value when you do different hold times ?

A The F sub zero is also called F physical, because i t is a parametrized process equivalent t ime at the reference temperature of 121 C with Z taken to be 10 C.

If you do a Log 6 overkill , that value is OK. But in reaily we work on retained bioburden with different decimal reduction t imes. Then, we have to arrive at a F and Z by T value.

Q What happens when the steam quality supplied is wrong ? What happens to validation ?

A That’s an operating conditions change and mandates requalif ication of process.

Validation has to be maintained within the l imits that are documented. Change control, which in i tself , is a writ ten procedure, and outlines the analysis and the implementation of change. This often necessiates repeating all elements on the validation studies.

I ts not only steam quality that demands change control. I ts venting, product loading, and, density, even changes in process control software, attract the full force of change control.

Q How often is requalification necessary i f nothing goes wrong .

A Usually, once in a year, assuming consistency in operational procedures and SOPs in calibration, maintenance, inprocess parameters, in process audits in other words, every activity that relates to end product assurance.

Q Why it is necessary to establish retained bioburden ?

A The US FDA says to describe and submit a procedure for routine monitoring of bioburden to ensure that established limits are not exceeded.

The industry position is that with log 6 overkill , there really is no need for this. Also where there is no substrate for microbial growth like a container, or inert i tems like closure, such a program is not called for.

Q What are the types of air samplers in use and what are their disadvantages ?

There are various air samplers that are available. The popularly used are :

(a) Cascade sampler :

A stack of agar plates is separated by perforated plates the perforations decreases in dimension, going from the top to the bottom of the stack. A sampling rate of 1.0 f t3 minimum, is maintained. Microorganisms attached to the

larger particles, impact on the top agar plate and those attached to smaller particles, cascade over, through the perforations, until they impact on a plate lower down in the stack. After the specified sampling time, the plates are incubated and examined.

(B) Slite to agar sample :

The air sample is drawn through slits and impinges on a rotating agar plate. Minimum impingement of the contaminants in the air sample is achieved by controlling the dimensions of the slits, the distance from the slits to the agar surface and the air f low.

(C) Single sieve to agar sampler :

The air sample is drawn through a perforated disc and impinges on a 55 mm agar contact plate.

(D) Centrifugal sampler :

The air sample is drawn onto the sampling head by means of an impeller. The impeller then directs the air onto an agar str ip fil led around the circumference of the sampling head. The air sampling is done for a specified t ime period, after which the agar str ip is removed and incubated.

(E) Filtration :

The air sample passes through a membrane fi l ter for a specified t ime period. The f il ter is then incubated on an agar plate.

(F) Liquid Impingement :

The air sample is drawn through an aspirator bottle containing a buffer or any other suitable medium. After the specified sampling time the solution is examined for the presence of microorganisms by a suitable method.

Each of these air sampling devices have several disadvantages.

The cascade sampler has a very low sampling rate to study the most crit ical environments.Only some of the slite to agar samplers can take a statistically large enough samples ( 3.0 - 3.5 m3) to enable the examination of critical environments. They are also rather cumbersome to use. Procedures for operating these samplers at higher sampling rates / longer sampling periods need validation.

The efficiency and sampling rate of the single sieve to agar sampler is even lower than that of sl it to agar samplers. The centrifugal sampling device is the most convenient use but there are so many uncertainities surrounding i ts sampling rate, that data interpretation is more difficult.

The f il tration technique can take statistically large enough samples but again the process needs validation.

The liquid impingement method introduces additional preparation procedures for the aspiration bottle and buffer solutions and procedures for recovery of contaminants. Care should be taken to prevent spillage of buffer solutions in the critical area.

Q How many media f i l l tests would be required to establish / validate an aseptic processing operation ? How often should these tests be performed ?

A There are no uniformity accepted criteria which indicate how many tests establish this procedure. But, Yes, what is accepted is that more than one media , f i l l test is required to evaluate a new processing operation. There are suggestions that three media f il l tests should be run for the initial validation. But, if three tests provide divergent results i t gives less assurance than two consecutive acceptable tests. What is important is that the number of tests should be based upon sound scientific and technical judgement rather than relying on any specific number of tests to be done.

Revalidation :

If no changes have been made to the manufacturing process and the media f il l test data and environment data

consistently meet specifications, then there is no need to perform more than one media fil l test in a year, for each aseptic processing operation :

However, the revalidation schedule should be based upon an evaluation of process changes, historical media fi l l test data and environmental monitoring data.

Q In general, , potent medicaments are not added during the dry mixing stage. These are generally added at the lubrication stage. Will this product pass the content uniformity test ?

A If possible, i t is advisable to add a potent drug in the dry mixing stage i tself , to ensure uniformity of mixing.

Whether the drug is added in the dry mixing or lubrication stage, the process should be validated.

The validation of the process would ensure uniformity of content, even if the drug is added in the lubrication stage.

Q It is noted that permeability of gases into formulations is much higher in plastics. Will this affect the shelf l i fe and efficiency of drugs as compared to similar formulations in glass bottles ?

A From the point of permeability, glass is definitely less permeable to gases when compared to plastics. Hence, the shelf l ife of formulations stored in these containers will vary.

Photosensitivity is another point to be considered. The plastic let in a totally different wavelength of l ight.

But, i t should be remembered that glass has the disadvantage of surface alkalinity and leaching of extractives.

Permeabili ty is only one of the factors which affects the shelflife. The self-life of a product in any pack depends on many factors, all of which would have to be examined before deciding between glass and plastic. These factors should be ascertained at the t ime of stability studies and

an indepth study carried out. The effect of the container should be factored in, before f ixing the shelflife of a product.

Q What is the maximum limit to store tablets in one single container ?

A By the words maximum l imit I consider t ime limit and would say that, every organization has different standards, depending on convenience.

Let us take an extreme case. A batch of tablets is packed in a bulk pack of thousands and sent to the market with a shelf l ife of say, 3 years that the tablets can be stored in the container for 3 years. Many companies are exporting bulk pack of 5,000 or 10,000 tablets, which means that the tablets are stored in the container for 3 years.

Extending the same logic, can i t be considered safe, if bigger bulk packs of tablets can be left on the shop floor for 3 years ? Before we answer this, please consider hermatically sealed containers sent to the market vis a vis tablets stored on the shop floor.

If we have to set t ime limits for storing tablets in a container, then one has to set l imits for storing granules before compression, and also a l imit for storing recovered tablets before processing.

My personal view is that, t ime limits for keeping tablets should not exceed more than 3 months. Otherwise, i t indicates bad planning, on part of all the departments of an organisation. Instead of keeping these tablets as such, i t is always better to keep these as a f inal pack because, then, i t is in a hermatically sealed pack.

Q What could be the best system for pest control in production manufacturing areas, where partit ions are made up of wood / plywood ?

A Please pull down the entire structure and go for aluminium and glass. No pest control should be done in production

areas. There is no guarantee that pesticides are not carried into the products.

Q Is i t necessary to boil the sugar syrup in l iquid products to 70 0C - 80 0C ? Why ?

A Most of the manufacturers make sugar syrup by the hot process. But, there are a few who make it by the cold process. Sugar is one of the ingredients which is bought in gunny bags by most of the manufacturers and so, i t is always safe to make the syrup by the hot process. If one has to make this without heating, the parameters to be considered are : what is the concentration of sugar going into l iquids, what is the quality of sugar and foreign matter, how long will the l iquid be kept under storage t i l l the final product is packed, how is i t stored and whether the product can withstand the preservative challenge test. We also should consider what is the quality of sugar over a period of one year and the quality of the syrup made with the same.

It is essential to validate your process and product fully with respect to the above mentioned points and new materials going into the l iquids. If you are confident and can assure the quality, you may use the cold process.

When the hot process is used, sugar syrup is prepared at a temperature which is around 65 0C and has a concentration of sugar, which is well above 60%. This will certainly prevent the growth and also kill many microorganisms.

Q Please describe the storage conditions, dispensing procedure and sampling procedure for cytotoxic drugs.

A For most of the raw materials, storage conditions and processing ( manufacturing ) conditions are the same. A few materials, whose init ial activity is l ikely to be affected by higher temperature, are kept at lower temperatures of 2 to 50C. Please take this into account before deciding storage conditions of cytotoxic drugs. There has to be an exclusive dispensing area with reverse laminar flow, and depending on the hazardous and potent nature of cytotoxic drugs, proper clothing, hood and mask should be provided, while

sampling. This can also be sampled in the production area, l ike steri le raw material sampling.

These questions have been answered by I .R. ThamankarG.M. Formulations Kopran

Q What is Dutch Mesh of f luidized bed dryer ? Does i t dif fer from conventional mesh for sifter ?

A The Dutch Mesh used in f luidized bed dryers is also known as Hollander Weave mesh. Twill Mesh or Multi mesh. This twill mesh is stronger when compared to the ordinary mesh. Owing to i ts durability, i t is more commonly used in f luidized bed systems as compared to the conventional mesh used in sif ters.

In the Dutch weave mesh, there are two different guages of wires used in the warp and weft of the wire screen, thereby imparting much more strength and durability to the screen. It therefore lasts longer and also withstands higher pressure as compared to a conventional mesh. The twill mesh also cleans more easily.

Q What’s is the material of construction of FBD bags ?

A Normaly, FBD bags consist of a fabric containing a mixture of polyester and cotton in equal proportions. Premium filter bags are generally made from epitropic cloth, which is essentially a carbon impregnated fabric. While the material cannot be considered to the antistatic, i t is at least conductive, so as to drain away electrostatic charge.

Q How do you protect punches from rusting when it is not permissible to use kerosene ?

A After compression, remove the powder adhering to the punches using a dry cloth. Then, soak the punches for f ive minutes in warm water which contains 20% detergent and clean them with a nylon brush. The punches are then dipped in plain water and wiped thoroughly using a dry cloth.

A small amount of lubrication oil is then applied, at the tip and other parts of the punches before storing them in the punch trolley or the punch box.

Q How can we reuse enteric coated tablet rejects ?

A A maximum of 2% of the rejects may be reused by adding them to a fresh batch.

The enteric coating part of the rejects is washed using acetone. The core tablets are them dried. After drying, the tablets are crushed. The crush is sieved through a 60 mesh sieve and the content / gm checked. The contents are calculated as per assay and added to a fresh batch at the time of formulation.

Note :

I t is not advisable to reuse the enteric coated rejects of highly hygroscopic tablets l ike sodium valproate

These questions have been answered by K.P. Lucasmani, Manager Production, Sun Pharmaceuticals, Chennai

Q What should be the acceptable tolerance limits for vitamin B12 and folic acid content in multi-vitamin tablets or capsules ?

Are formulations of multi-vitamins specified in any of the Pharmacopoeias ? What should be the minimum limit of these drugs during their Shelf l ife period ?

A Some formulations, mostly tablets and capsules are official in the Pharmacopoeias. In the USP, preparation of both, water souble and fat soluble vitamins are official. These include Decavit, Hexavit and Oleovit which contain vitamin A.,D, calcium, pantothenate and the Bcomplex vitamins. There are no official products prescribed in the IP. If the product is official, then the l imits should be as per the pharmacopoeia. Otherwise, they should conform to the Schedule V of the Drug and Cosmetic Act. 1940 This schedule lays down the standards for patent or proprietary medicines.

The standards prescribed do not apply to preparations containing a single vitamin only and to any preparation containing vitamins for parenteral use. These l imits are relaxed for patent and proprietary preparations containing vitamins intended for the treatment of specific conditions or diseases. In such cases the Licensing Authority may permit the addition of vitamins, if satisfactory evidence is produced to justify such a relaxation.

For preparation containing vitamins, only a lower l imit of 90% is applicable. That is, the content of active ingredients in a vitamin preparation shall not be less than 90% which is also the shelf l ife of the drug.

The dosage limits of vitamins B12 and folic acid are given in the Table below.

Q In the case of a loan license manufacturers, for how long should the records of manufacture be retained by the manufacturer ?

A The records retention requirements for a loan l icense manufacturer, that is a contract manufacturer are the same as that for a principal manufacturer.

The retention t ime for all classes of drugs is for f ive years after the date of manufacture.

The loan licensee should posses all documents records pertaining to the manufacture of a batch, so that a complete product history of the drug is maintained. The loan licensee may enter into an agreement with the manufacture to the effect that all the records will be available with the manufacturer. The records must then be kept at the manufacturer’s facili ty. If they are maintained elsewhere, i t should be possible to retrieve them immediately by computer or other means.

Q During repackaging, is i t allowed to allot a single batch number, to two or more mixed lots of bulk f inished product repacked during the same run.

A Allotting a single batch number to a mixed batch of the finished product, even if the records clearly indicate and

identify the batches that are being mixed, would cause the finished repackaged product to be a violation of cGMP norms.

Identifying problem lots or batches in the event of a complaint or f inding of a defective product, assigning appropriate expiry dates, and collection of representative samples may be a problem when batches are mixed together.

These questions have been answered by Mr. M Kannan, Senior Drug Inspector, Drug Control Dept. Chennai.

Q How important is testing for microbial contamination in non- sterile products ?

A cGMP regulations require that there should be written procedures for prevention of microbial contamination in nonsterile products. These should ensure that there is no contamination or growth of organisms in a product. The prevention of microbial contamination should be evaluated on a case to case basis, depending on speciation, number of organism type and use of dosage form, route of administration etc.

Microbial contamination in a product could adversely affect i ts stability, react with or, damage the container system, interfere with analysis affect bioavailabili ty and pose a threat to efficacy of treatment. I t is also important to establish production t ime l imit to prevent microbial contamination. Time limits for one completion of every phase of production must be established and followed.

Q. According to cGMP is i t necessary to have different departments for the Cephalosporins and Penicillin formulations ( dry powder Injections ) ? If so, why when they are of the same B-lactam group ? Also, please let us know whether these departments should have separate building or block as per the U.S. FDA ?

A. An anaphylactic reaction to penicill in or for that matter to cephalosporin - can be l ife threatening.In the U.S. regulations for control of penicillin cross contamination came into effect in 1969. About that t ime,

methods for detection and quantif ications of residual B-lactam antibiotics were evolved by what is now known as NCAA ( National Centre for Antibiotic Analysis ) .

Those methods, now outdated, gave a LOD (Limit of Detectability ) of 5 ppm for cephalosporin and, near zich for ampicillin. Naturally, that inadequacy combined with the gross detection by the FDA and the Industry of penicillin in non - antibiotic preparations let cGMP to mean segregated manufacturing facilit ies.

The microbial analytical approach gave so specifically in the analysis of drug residues, until Herbst in 1975 proposed the Bioautographic method that give a LOD of 0.5 ppm.

Dr. Meera, besides detection, a vital requirement for cross contamination control is your abil ity to inactivate the contaminant.

Please refer to Methods in Enzymology Vol. XLIII Antibiotics Academic Press Many different enzymes are capable of catalyzing the hydrolysis of the B Lactam ring, and that, B-Lactamases from at least 25 different strains of bacteria have been purified and studied. Since B-lactamase preparations are not standardized and are available from many different sources, care must be exercise by the laboratory to employ a suitable B-Lactamase preparation of sufficient t i ter, to provide proper inactivation under specified analytical conditions.

The B-Lactamase inactivation of the test solution may produce the following results :

1) Complete inactivation (a positive test ) : The loss of activity of a treated versus an untreated aliquot of the sample solution indicates that a B-lactam residue was present. A quantitative determination of the residue can be made in terms of an appropriate standard.

2) Incomplete inactivation ( a presumptive test ) : A significant reduction in the activity of treated versus untreated aliquots of the sample solution indicates that a B-lactam residue

was present, but that other active agents or ingredients have caused interference problems. Accurate quantitation of the B-lactam residue is not possible under these conditions.

3) No activation (a false test ) : No significant reduction in the activity of treated versus untreated aliquotes of the sample solution indicates that interfering agents or ingredients may be masking the presence of a B-lactam residue. No quanlitative or quantitative analysis can be made of the residue.

4) No activity ( a negative test ) The absence of zones of inhibition from treated and untreated aliquots of the sample solution indicates that no B-lactam residues has been detected ( within the l imitations of the test method )

Now comes my opinion not an answer. Separate AHU makes sense. Separate block, better sense, separate building, best sense ?

Normally, is our LAF’s the Air Velocity should be 90 + 20 CFM. During validation. I found out that some of the HEPA Filters located in supply duct of class 1000 Area, were having Air Velocity of 250 CFM, which seems to be quite high and detrimental to HEPA Filter as well as aspectic area. Kindly comment. Also, what are the possible il l effects of such a type of system ?

Rajiv, if you don’t mind, I will somewhat broad base the reply.

Laminarily, or lack of turbulence, is the design intent of all systems where one works in ciose proximity of a HEPA futer.

For horizontal use, air velocities upto 0.7, m/sec the upper threshold are f ine, provided you have l inear containment of the airflow, l ike a canopy, sides, and a table. Values must respect cross section aspect ratios.

For vertical airf low :

With gravity as a natural vector this value goes down to 0.4 m/sec. And, the U.S. Industry tends to 0.35 m/sec.

The new standards have dropped the description LAMINAR for the more apt Undirectional, and, give no l imits for velocity, implying that laminarity is case determined, call ing for a one on one analysis of User needs. I t cannot be brochure specific.

Coming to the other applications. Terminally mounted HEPA Filters are called mixed f low systems the volumes of air is predicated by the number of air changes per hour in the clean room. That is the criteria. Consequently, the airflow is designed to be maximal for that particular fi l ter size. The threshold velocities are 1.5 m / sec. Which is the usual rating for a 2000 m3 / Hr capacity HEPA filter . Capital and operational costs are minimal.’

In aseptic processing areas that velocity is too high, as intra zone over pressure control cannot be ramped. I t is best to stay with 0.75 m/sec Operational costs are less, but, capital costs are inversely proportional, while functionally, the area performance is directly proportional.

The other i l l effects of higher exit face velocities are the bellow back within the HEPA matrix, particularly, in exchange areas. That assists grow through conditions as until recently terminally mounted HEPA were made to fil ter air at near dew point. Micro droplets excasebrated lead to higher plate counts during the monsoons.

Those problems have, of course, been fully overcome today with the new enhanced performance HEPA Filters.These queries have been replied by B. Singhania.

Do we have special coated punches and dies for special toolings are available for compressing materials containing salts or products that cause rusting. Some options are a. High Chrome High Carbon ( HCHC ) steel can be used to minimise rusting. As this steel is britt le, punch cavity should preferably be selected as shallow concave to prevent chipping of edges ;

h Oil Hardened Non Shrinkage ( OHNS ) Steel for punches with hard chrome plating can prevent rusting upto some extent :

c Hardenable stainless steel can be used for punches, but compression pressure has to be restricted. However, this steel is not available indigenously.

Types of Breaklines ( A-G) are they followed by all tool manufacturers as standard ?Dust cap : cleaning after compression - how convenient is i t ? Regrinding of punch tip : is i t possible for the monogranted punches also ?

Types of Breaklines ( A-G) are not yet followed by all the tool manufacturers in India. However, they are followed as standards in European Countries.

Dust Caps :

Two types of dust caps are used to keep upper punch dust free, so that cleaning frequency of upper punch is minimised.

Type A :

Elastomeric Caps f ined on the upper punch tip. In this type the upper punch shank is prevented from dust marginaly (25%). Individual Rubber cap has to be procured for different size of table.

Type B :

Elastomeric seat and “rubber” bellows are fit ted on upper punch shank. This system prevents dust from reaching the punch shank to a great extent (80%) Upper punch shank has to be modified so that “rubber” seat can be fi t ted.

Common rubber seat and bellow are used for all size of tablet, available indigenously for “B” tooling.Regrinding of punch cavity is possible only in round, concave cavity without monogram. An existing monogram can be removed by regrinding but not vice versa.

Q Wha is impurity profile ?Sipali Pharmaceuticals

A An impurity profile is a l ist of all possible related substances that could be present in a compound.

The USP defines an impurity profile as a description of the impurities present in a typical lot of drug substance produced by a given manufacturing process.This standard profile is developed early on during the developments and stability studies of a pharmaceutical compound and a record should be maintained of this exhaustive study. Each commercial lot of a compound should be comparable to this record. This profile could also be called the reference profile. The Quality control department would refer to this profile for assessing the purity of a batch of an active ingredient and when evaluating any process changes.

An impurity profile should give certain basic information of impurities present at or above the 0.1% level or sometimes even lower depending on the toxicity of a compound.

The information includes :

* Test of identity* Ranges normally found* Limits* Description of the impurity

Whether i t is an in- process decomposition product, unreacted intermediate, etc.

The methods developed for detecting impurities should be appropriately sensitive and capable of detecting and quantifying the impurit ies.

At least two methods ( e.g. HPLC, GC ) could be used for the routine purity testing of a pharmaceutical compound.Identifying and developing an impurity profile for an active pharmaceutial susbstance is consistent with cGMP.

Q Should active ingredients be tested only for those impurities stated in the Pharmacopoeial monograph, or must batches be suff iciently characterised for purity ?

A The monograph in any pharmacopoeia cannot l ist out tests for every impurity, contaminant ( including microbial ) or adulterant that might be present. These could arise from a change in the source of material , changes in processing or from an extraneous source. Tests suitable for detecting such substances should be employed in addition in the tests provided in the individual monograph.

The USP supplement V ( official Nov. 15, 1996 ) states that for active Ingredients major impurities ( 0.1% or greater) which are not l isted in the product monograph and cannot be reliably analysed by i ts methods should be named, quantif ied and included in the certif icate of analysis of the official substance. For those impurities for which toxicity is a concern a lower qualif ication threshold and more stringent specifications should be prescribed.

Q What should be done with a raw material which conforms to all the standards laid down in the respective monographs of IP / USP / BP, but gives positive tests for other types of impurities which are not mentioned in the monograph ?

A If the impurity is not mentioned in the official monographs and in the company’s internal specifications, i t is legal to go ahead and use the raw material .None the less, having detected the impurity, i t is essential that i t should be quantified and investigated with the help of l i terature. If i t is ascertained that there might be any kind of adverse effects because of the impurity, i t must be put on hold.

But, irrespective of whether i t causes, adverse effects or not, the presence of such impurities should be taken up with the supplier of the raw material and steps taken to ensure that these additional impurit ies are eliminated.

Q In formulating a batch to provide not less than 100% of the labelled or established amount of active ingredient, most firms consider such ingredient attributes as assayed potency and water content ?

A It is an essential of GMP to consider assay, values, water content and any other factors that might affect the potency of batch during formulations.

If a batch is labelled 100% but the active ingredient is known to contain about 5% of moisture, the effective potency of the formulation is 95% And it is also possible that there might be variation, depending on the actual moisture present. So, we have batches which contain 96%, 97%, 95% and so on, of the active ingredient. Establishing a shelf l ife becomes complicated

So, the moisture content should be factored into the calculations to ensure that all batches contain 100% of the active ingredient.

Q When the labelled expiration date states only the month and the year, does that mean that the drug expires at the end of the specified month ?

A If the expiry date states, for, e.g. Feb. 1998, i t means that the drug expires on the last day of February 1998. If the text states use before February 1998 the drug expires on the last day of January 1998

Q Most IP grade active ingredients be tested in accordance with IP monograhs ?

Q Must manufacturers test each batch for all monograph specifications ?

A The official speicifications are the minimum requirements of a pharmaceutical compound. The in house specification are tighter and more stringent than those laid that in the Pharmacopeia.

Active ingredients must be tested for all specifications and all batches must be characterised as per the specifications.

Q How is the moisture content of granules in a f luidised bed drier measure ?

A Generally, in a f luidised bed drier, the drying is complete when the outer temperature becomes equal to the inlet temperature. By providing a digital temperature indicator,

and monitoring the outlet temperature the moisture content of the material in a FBD may be determined. But, this is not a pragmatic method and the best way to determine this may be by the conventional IR balance method.

There is also a device developed in Germany whereby a probe is placed inside the chamber of the FBD, which measures the humidity and converts i t to the moisture content of the material.

Q What is the technical purpose a breakline on upper punch and lower punch ?

A There is no technical purpose for providing break line on upper punch and lower punch. Break line is provided only for the convenience of taking half the dose if required.

Q What are the main raw materials used for manufacturing membrane fi l ters ?

A The most common f ilters in use are made of cellulose esters l ike cellulose nitrate or acetate. Membranes are also made from rayon, polycarbonate, nylon, polyvinylchloride, polypropylene, teflon, and even gelatin.

Microporous membranes are made from a polymer solution by a process of phase inversion. The factors involved are temperature. , water vapour inhibition and exchange of solvents with non solvents. The pores are neither cylindrical nor triangular but can be best described as random polymeric froth consisting of 80% void volume.

Q What is the effect of steam sterilization on membrane fil ters ? What happens at higher temperature ?

A Reverse phase membranes are the f il ters used almost exclusively for sterilization by fi l tration. During casing strain and molecular orientation are builts into the membrane. The heating process may relieve the strain Plasticization of the f il ter by heat occurs because the viscocity of the fi l ter is reduced at elevated temperature enabling movement and adjustment of the polymer segments. As a result, changes take place in the fil ter pores. Usually, the pores shrink, and the bubble point of the f il ter rises. I t

is also possible that some pores due to stress become larger even while other are shrinking.

So it is a r isk to repeatedly sterilize membrane fi l ters.In case of repeated sterilization, the bubble point test before commencement of the f il treation proces is a must.

Q Why can’t we use lactose as diluent in isoniazid tablets ?

A Since lactose interacts with INH to form isonicotynyl hydrazone, which is absorbed poorly from the GIT, i t should not be used in the formulation. More over, INH undergoes Mailard reaction with lactose and darkens the colour of the tablet.

Q Does f inished product ( FP ) testing provide us with an unbiased view of the f inished dosage form, or do we only perform FP testing to satisfy the requirements of the Regulatory Authorities ?

A Finished product testing in insolation does not provide an unbaised view of the product. FP testing, done after the process is complete, substantiates the results of the In Process Control (IPC ) testing. To obtain an exact picture both the IPC and the FP tests should be considered. This would prove that the product conforms to i ts specifications. FP testing cross checks the integrity of the product, and therefore is more than a procedural formality.

If the testing proves conformance, the Regulatory Authorities will be satisfied anyway.

Q Do IPC results carry more credibili ty than the results of FP testing ?

A All organisations have established certain critical parameters for their products, which are monitored by IPC. While IPC documents and validates the process, FP testing is a natural progression to conclusively proving the integrity of the process. As FP re-establishes the claims of IPC, of the product conforming to standards, i t is equally important.

Q Should products tested always pass the FP specifications before i ts release ? Can IPC data be taken into account i f the results obtained with EP are outside the specification ? Should these results influence the decision to release the product ?

A As stated earlier , IPC and EP testing should complement each other. This proves that the process is under control. In a fully validated process, if the IPC results meet the requirements, the results of FP testing will meet the specifications. When this is not so, resampling of the finished product could be done. If the EP results are outside specifications, the matter has to be completely investigated, and the results documented. The f inal decision of release then rests with the Quality Control Department based on their f indings.

Q How do we set the IPC specifications and l imits ?

A Normally, the pharmacopeial specifications are the basis on which any process parameters are built . The IPC specifications are more str ingent than the pharmacopeial l imits, so as to make allowances for any possible variations during the various stages of production. The FP limits too, are equally if not more, stringent than the IPC l imits. These parameters are established during the validation process.

Q Who should perform the IPCs ? Also, can IPC data generated by production personnel be used for f inal product release by the quality Control Department ?

Both the production department and the QC department should perform the IPCs, independent of each other. The data generated by the production department serves as their guideline for controlling the manufacturing process. Decisions taken by the Quality control must be based on the compliance of results with specifications. IPC data recorded by the production department can certainly be taken into account by the QC if necessary. But, they make the final decision on the release of the product.

Q Should the IPC and FP tests performed be derived entirely as a result of validation studies ? If so, for established

processes, i f the balance between IPC and EP testing is modified, then should revalidation also be carried out ?

A IPC and FP tests are validated at the conception level of any process. This is a joint exercise involving the R&D or the Product Development, Production and Quality Assurance personnel. Other departments l ike Engineering Supplier of Raw Materials may also be involved. Revalidation becomes necessary when there is any change in the process, change in mixer capacity, modification of aseptic area.

It is recommended that the established process be validated once in every six months.

Q What are the people / procedural factors which are important to ensure successful application of an IPC / FP testing system ?

Errors of any kind can cause have to a system in these days of automation. People play and will continue to play an important role in ensuring the success of any system. The organisation should select and carefully train i ts personnel to meet the demands of excellence required by the Pharma Industry.

Operator training on any testing procedure needs a thorough knowledge of the Standard Operating Procedures written for that test to be executed. This step is probably the most time consuming component of the training process.

Learning and applying a process not only requires physical and intellectual abilit ies but also involves the development and persistance of a correct mental atti tude.

Q It is very difficult to handle materials which develop high electrostatic charge, especially during dry granulation. What can be done to neutralize ( partially or completely ) , to have a clean operation ?

A ESD ( electrostatic discharge ) or ZAP in Electronics and Corona in the Pharma Industry, can tr igger at even 1000 volts, white dry granulation reaches 35,000 volts at 15% RH.

The solution l ies in a proper salt pit earthing of the granulator. Another solution is using only ionising process air, after etablishing the electrostatic polarity of the materials. Adding excipients that function as hygroscopic cells ( any number of them both organic and inorganic ) which draw away, hold or dissipate the static charge could also help.

Not any but all of these methods may be necessary.Just a bit of triva Tajinder, check to cheek greeting can tingle at 3000 Volts ?

Q Since the present US FDA regulations are objecting to the fumigation of the area using formaldehyde and Potassium Permanganate, due to post carcinogenic effects, is there any effective method to fumigate the area ?

A Hydrogen peroxide Fumigation is the ideal method which can be used.

Q Each LAF module comes equipped with a pressure gauge. What does this pressure indicate ? How is i t measured, i .e. what are the two points considered to measure the differential ? Is the pressure measured in terms of water is necessary ? What are the limits of pressure beyond which one should get the module checked ?

A Each LAF unit is equipped with a manometer or a magnabelic gauge to indicate the plennum pressure with respect to ambient. The indicated pressure i tself is the differental pressure differential with respect to ambient.

The plenum presure may vary slightly from equipment to equipment. This is due to the density of the HEPA media.

When equipment is installed and demonstrated, a note should be made of the initial indicated pressure, as this becomes the reference base for future.

When a prefil ter gets choked up, the intake air quantity is reduced, thus building lesser plenum pressure with respect to init ially noted manometer ( or gauge ) reading. This is an indicator calling for action “ Pre Filter Needs Cleaning “

When the HEPA filter gets choked up, the air f low is reduced. The plenum pressure naturally increases beyond the init ially noted reading. Normally all HEPA filter have a longevity beyond two years, subject to disciplines maintained and the plenum could go upto 17 to 18 mm, beyond the previously noted pressure reading. When the pressure goes up, and velocity reduced below 0.4 M/sec. HEPA fil ter have to be changed.

A check should be carried out once in every six months to assure the quality air is maintained continuously.Manometer pressure reading is alwa in millimeters of water not mercury. So is the case with magnethlic gauges.

Q What is the best SOP for checking the accuracy of marking line, such as 2.5 ml, 5 ml in deep coloured plastic measuring glass, provided with l iquid oral bottles ?

A Purified water is added upto the marking line using a calibrated pipette and the volume delivered is measured. The same procedure is followed even for coloured / opaque measuring cups. I t is generally advisable to provide transparent measuring cups for the convenience of the consumer.

General information section ( 1221 ) of USP, under the t i t le teaspoon, specifies that the volume error incurred in measuring liquids using such devices, should be, not greater than 10% of the indicated amount.

Q What is the requirement for intensity of l ight required for carrying out various operations in the manufacturing of tablets and parenterals ?

A The intensity of l ight required in the manufacturing area for carrying out various processes is 300 to 400 lux. For visual inspection, the intensity required is 160 feet candle at the working level.

Q How can we reuse the enteric coated tablets rejection ?

A GMP requirements permit reuse only if the quality of the final product is not affected and additional testing of

finished product, into which a recovered product has been incorporated. Is carried out, if required.

Effect on the product attributes. On introduction of polymers used for enteric coating in the core tablets, is less predicatable. I t may affect the physical parameters as well as availability of the drug adversely. Therefore, reuse of enteric coated tablets, either by intorudction into a subsequent batch or, by processing the pooled residue as a separate batch, is not advisable.

Q What are the sanitizing solutions to be used, with rotation and frequency for.

a Cleaning of f loorsb Cleaning of equipmentc Epoxy coated walls and glass panels

Unique Pharmaceutical Labs.

A For sanitization of f loors, walls, and glass panels, Lysol (Cresol ) , Dettol 5% ( Chloroxylenol ) Savlon 2% (Chlorohexidine Gluconate and Cetrimide ), are recommended. The disinfectants are used in rotation and should be changed on a weekly basis.

For cleaning of equipment, use of 0.1% sodium lauryl sulphate solution and for sanitization of equipment use of f il tered steam is recommended. For drying of washed equipment, infra-red driers are being used currently, which avoids the use of mops.

Effective cleaning is 90% of the overall sanitizing job and application of sanitisers is the remaining 10%. Therefore sanitization responsibilit ies should be performed by trained and reliable people.

Q What is the best SOP for validation of ampoule washing machine.

A Validation of a machine will depend upon the type of washing process employed, such as jet washing, ultrasonic cleaning before jet washing etc. The operating variables generally change with the type of machine used.

Control of these variables during the washing process should be established before checking the cleaning performance. Some of the important variables and necessary verifications to be carried out are l isted below :

* All the measuring devices should be calibrated.

* Adequacy of the air and water pressure should be confirmed.

* Cleanliness and proper mounting of air and water f il ters should be confirmed .

* It should be ensured that all the washing needles are open and the required quantity of water is delivered in each washing cycle.

Effectiveness of cleaning can then be checked on washed ampoules as described below :

* The washed ampoules of a wash cycle are collected under a laminar air f low work station.

* The ampoules are f il ter with distil led water, f i l tered through 0.2 micron membrane fi l ter and the open ends are closed with aluminium foil .

* These ampoules are visually examined for presence of particulate matter.

The washing process can be continued if the percentage rejects are found to be within acceptable l imits.

Q What are the methods of sampling in the course of evaluation of cleaning validation ?

A There are two general types of sampling that are acceptable. The best method is direct sampling of the surface of the equipment. The second method is the use of r inse solution.

Direct surface sampling :

The f irst step is determined by the type of sampling material used and its impact on the test data, since the sampling materials may interfere with the test . I t is very important, early in the validation program, to ensure that the sampling medium and the solvent are satisfactory and can be readily used.

Advantages of direct sampling are that, the areas hardest to clean and which are reasonably accessible can be evaluated, thus establishing a level of contamination or residue per given surface area. Additionally, residues that are dired out or are insoluble, can be sampled by physical removal.

Rinse sampling :

The advantage of r inse sampling is that a larger surface area may be sampled and systems that cannot be routinely disassembled can be sampled and evaluated.

Disadvantages of the method are that the residue or contaminant may not be soluble or may be physically occluded in the equipment.

Routine production In process Control.

Monitoring and indirect testing, such as conductivity testing may be of some value for routine monitoring once a cleaning process has been validated. This could particularly be true for the bulk drug substance manufacturer where reactors and centrifuges and piping between large equipment can be sampled only using r inse solution samples. During validation, the firm should document that, testing the uncleaned equipment gives not acceptable result for the indirect test.

Q Is there any other method of depyrogenation other than dry heat ?

A Apart from dry heat steri lization, there are two method of depyrogenation i .e. by endotoxin removed and by endotoxin inactivation.

Endotoxin removal can be achieved by the following methods :

Rinsing

This is the oldest and simplest method of removal of pyrogens from solid surfaces. These are rinsed with non pyrogenic solvents, usually sterile water for Injection. Low levels of surface endotoxin contamination can be effectively removed from glassware, device components and stoppers.

Rinse water can be monitored throughout the process with LAL to validate endotoxin removal.

Disti llation

This method is used to remove pyrogen from water.Water is forced to undergo two phase changes, from liquid to vapour and from vapour to l iquid. Because the lipopolysaccharide is a large molecule, i t can not boil as rapidly as water and is left behind. Those molecules entrained in water droplets carried in the stream are dropped back by gravity due to their high molecular weight.

* Ultra Filtration

Ultra f il tration membranes are rated on the basis of molecular weight exclusion limits and their effectiveness as depyrogenating fil ters is due to their action as size discriminating screen. Thus, endotoxin that exceed the molecular weight exclusion limit of a given membrane are retained on the surface of the membrane.

The basic sub-unit size of a lipopolysaccharide is 10,000 to 20,000. It can therefore be effectively removed from solutions by a 10,000 molecular weight ultra f il ter.

* Reverse Osmosis

Reverse osmosis membranes consist of cellulose acetate or polyamide materials with pores small enough to exclude ions. Conventional reverse osmosis membranes ( normally rated pore size 10 A ) remove endotoxin by simple size exclusion. The pores in the membrane are far too small to pass the pyrogens.

* Activated Carbon

Depyrognation of solutions can be done based on the physical adsorption of endotoxin to charcoal particularly activated charcoal. Charcoal is added to the solution and agitated and the carbon is removed by fil tration. This is widely used in pharmaceuticals. But carbon has a tendency of absorbing the active ingredients in the solution since i t has an affinity for high molecular weight substances.

* Electrostatic attraction

This is achieved by using depth fi l tration, using asbestos which adsorbs the endotoxins. Endotoxin Inactivation can be done by the following methods :

* Acid base hydrolysis* Oxidation* Alkylation* Moist heat treatment

Normal autoclaving is not effective for depyrogenation, only long drastic heating would destory pyrogens. Example autoclaving at 20 psi for 5 hrs. At pH 8.2 or 20 psi for 2 hrs. At pH 3.8.

* Ionizing Radiationusing 60 C.

* Using Polymyxin BThese are the different methods of depyrogenation which can be used based on suitability. Each process should be validated before use.

Q We are calibrating HPLC equipment. I .e. pump ( f low check ) detector, injector / auto injector and system suitability tests as per USP XXIII I t is recommended that this calibration be done once a month. We are ensuring that the percentage relative standard deviation of six replicate injections of standard preparation is below 1.5%

For day to dry routine product release, is i t necessary to take six replicate injections of standard preparation all the time ? Or is monthly calibration data sufficient ?

A The USP XXIII requires that unless otherwise specified in the individual monograph, five replicate injections of the analyte are required for calculation of the RSD, if the RSD is 2% or less, and six replicate injections, if the RSD is greater than 2%. Hence, if one wants to comply with the USP in totally i t will be essential to carry out the exercise on a day to day basis. However, if the wording old preparations in the question means established products for which the HPLC method in use has been fully validated and adequately documented, then i t is possible to carry out tr iplicate or duplicate injections for day to day analysis and follow the USP protocol at defined intervals of say 3 months, as a part of revalidation exercise. This deviation from the the USP must be covered by an SOP.

Q What is the calibration frequency for mercury in glass thermometers ? I understand that glass thermometer calibration is valid for a l i fe t ime. Is i t so ?

A Mercury in glass thermometers can remain within calibration for several years, provided the same is stored and handled in a controlled manner. However, unless a thermometer is identif ied as a master calibrated thermometer, and stored and handled in a controlled manner as defined in an SOP, thermometers must be calibrated annually as part of GLP.

Q How are humidity control ovens calibrated for both humidity as well as temperature ?

A Humidity, control ovens can be calibrated for humidity using a calibrated wet and dry bulb thermometer, or by using primary standard chemicals, which can give established humidity in saturated solutions in contact with a solid. For temperature calibration, use any calibrated thermometers.

These questions have been answered by Mr. R. Raghunandan. Corporate Quality Manager, Glaxo India Lts.

Q What kind of regulatory clearances does one need to have for exporting Ayurvedic formulation ?

A If an Ayurvedic formulation is permitted to be manufactured and marketed in India, we would not require any other clearances from the Drug Control Administration for exporting the Ayrvedic formulations. However, there is a ban on the export of certain plant materials, either in the crude form, their extracts or formulations.

Q Should sil icon emulsion used to coat vials and stoppers be fil tered ? What is the most effective method for f i l tering sil icon emulsion ?

A The si licon emulsion used for coating should definitely be filteed. This is done to free the emulsion from particulate matter which might settle on the l ining. Any particulate matter settl ing on the vial would results in poor coating.

The best method is to f il ter through a 0.3 micron cellulose membrane fil ter .

Q What is the normal sampling time and sampling volume using an air sampler. What would be the ideal sampling procedure ? What should be the frequency of sampling ?

A The normal sampling volume using an air sampler, would be 3000 li tres at a t ime, at a particular place. I t is essential to make same that the corners of the room are definitely included in the sampling. Other than that, two or three places, in the room should be sampled. The number, posit ion and sample volumes should reflect the standard of control required, the level of occupancy and activity.

Monitoring for class V1 and class hundred should be carried out as close to the critical zone as possible. This may require a considerable developmental input to establish a practical method.

The frequency of sampling is determined by in house practice, based on procedures that have been validated. However, the following is the frequency as indicated in contamination control practice.

Class Frequency

V1 Daily or batchwiseV2 DailyV3 DailyV4 / V5 Weekly100 Daily1,000 Daily10,000 Weekly

Q What are the optimum storage conditions prescribed for rubber stoppers ? How should they be handled ?

A Rubber stoppers, before steril ization, should be stored in HDPE bags, in loosely packed numbers, as otherwise they would tend to stick to each other. These bags are stored at room temperature ( less than 35 C ) at a relative humidity of about 45% The stoppers should be protected from dust as the dust tends to st ick to the stoppers and their removal is very difficult. They should also be protected from grease and oil as rubber stoppers absorb oil and swell up.

The stoppers are sterilized immersed in water for injection along with a preservative double the concentration of that used in the f inal product. The level of water should be enough to compensate for any loss during the sterilization process.

If i t is required that the stoppers should be dried, the drying should be done in a hot air oven f it ted with HEPA filters, at temperatures less than 100 C Repeated sterilization of the stoppers should be avoided. If the stopper are to be stored, i t is better that they be stored in a dry condition.