sterlization - eduwavepool.unizwa.edu.om applied filter paper should not ... based on using aseptic...
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STERLIZATION
Sterilization of parenterals
Aseptic technique:- is the preparation of pharmaceutical products
from sterile ingredients by procedure that exclude the access of viable
microorganism into the products
It is used for those would be adversely affected by being subjected to
sterilization
Sterilization = complete removal or killing of all viable
microorganism and their spores
Microorganism can be
categorized into three types
Easy to kill by dry or moist heat
Susceptible to moist heat and resistant to dry
heat
Susceptible to dry heat and
resistant to moist heat
1- Dry- heat sterilization
2- Steam sterilization
3- Sterilization by filtration
4- Gas sterilization
5- Sterilization by ionization
• However the applied method for sterilization the product must pass the sterility test.
Important to:-
• As a proof of the effectiveness of :
• the applied method,
• Performance of the equipment
• Performance of personal
1- Dry sterilization (Oven method
• Less effective in killing M.O , • so higher temp and longer time of exposure are required. • Temp of 140 ° for 3 hrs or 260 ° for 45 mins are efficient to
kill spores and vegetable M.O
• (due to dehydration of microbial cell followed by a slow burning or oxidative process)
Dry sterilization use Ovens The modern ovens are supplied by heated, filtered air that is
uniformly distributed throughout the oven chamber
1- Used for heat stable non-aqueous preparations, powders, 2- small individual units to permit free circulation of heated air
3- equipment (glass , porcelain, not for plastic) 4- heat stable powders (kaolin, sulfur, Zno…) 5- Surgical instrument 6- Substances that can not sterilized by moist heat (Fixed oil, Glycerin, petrolatum, paraffin)
1- Dry heat method usually applied to:
2- Moist heat sterilization • Based on heating in saturated steam under pressure • More effective in killing M.O than dry method.
• The BP & EP recommended 121 ° C maintained throughout the load for 15 mins as the preferred combination for this method of terminal .
• So pressure is applied to achieve higher temp. Autoclaves that employ steam under pressure which ensure destroying
spores bacteria within 20 mins at 15 pounds (temp = 132)
a- Moist heat cause denaturation or coagulation of
bacterial cell protein at much lower temp
B-Thermal capacity of the steam is greater than that of
hot air
Steam sterilization is applicable to
1. Aqueous solution packed in sealed containers as ampoules
2.Bulk solutions
3.Glassware
4.Surgical dressing and instruments
5.Can be applied with temp lower than 100 °C (suitable for substances not withstand higher temp.
Not suitable for :
1.Oils, fats
2.Preparation that not penetrated by moist
3.Powders that may be damaged by moisture
3- Sterilization by filtration
• Used to remove particles including M.O from solutions from or gasses (air) by :
• - adsorption on the filter paper
• Sieving mechanism
• The applied filter paper should not remove the desired constituents or add any undesired constituents.
• Applied for heat sensitive solutions
• Filters are two basic type:
• Depth and membrane
Based on combination with
pathway and adsorption to
retain M.O or particles
Based on sieving
through the filter
pores
Membrane filter media Millipore filter
• Plastic filter
- Cellulose nitrate
- Cellulose acetate
- Acrylic copolymer with nylon
- Polysulfonate
Sintered glass or
metal filter
Used when durable
characteristics are
required
laboratory for filtration sterilization of medium components. The filter is
placed (aseptically) on the glass platform, then the funnel is clamped and the fluid is
drawn by vacuum into a previously sterilized flask. The recommended size filter that
will exclude the smallest bacterial cells is 0.22 micron.
Gas sterilization
• Applied for heat & moisture sensitive materials
Ethylene oxide Propylene oxide
Flammable gases usually applied after
mixing with inert gases
Sterilization time 4-16 hrs
Ethylene oxide (ETO) is the most commonly used form of chemical
sterilization.
Due to its low boiling point of 10.4ºC at atmospheric pressure, EtO)
behaves as a gas at room temperature.
The sterilization process is carried out in a specialized gas chamber..
An ethylene oxide sterilization gas chamber
• ethylene oxide interfere with the metabolism of bacterial cell .
mode of action:
Application:
Applied for thermolabile
materials, without damage
medical and surgical supplies
such as -- catheters, needles,
plastic disposable syringes in
their final packaging
The gas can diffuse
through packaging
materials and containers
made of paper, fabric, a
range of plastics & rubber
And diffuse out again after
sterilization
EtO chemically reacts with
amino acids, proteins, and DNA
to prevent microbial
reproduction.
Sterilization by ionizing radiation
•applied by electromagentic waves e.g – •gamma rays --- Infrared radiation --- X- rays •Ultraviolet light (wavelength near 265 nm are the most effective, as they are strongly absorbed by nucleoproteins) • (Disadv. Of U.V = poor penetrating power) •Applied to clean air , water in thin layers
Ionizing radiation by gamma radiation have high penetrating power and high sterilizing efficiency, little or no damage effect on irradiated materials
Is the most common in UK & used radioisotope coblet 60Co
But still limited technique bec: require of specialized equipment
undesirable effect on products and containers
Mode of action:- ionizing radiation cause excitation, ionization
and where water is present, free radical formation
Free radicals are powerful oxidizing agents&
capable of damaging essential molecules in living cells
WEEK 12
•VALIDATION OF
STERILITY
Validation of sterility
• Regardless the applied method for
sterilization, Sterility test must confirm the
absence of viable micro-organisms in samples
taken from production batch
1- Sterility test
Direct transfer
to test media
membrane filtration
technique
Direct transfer
to test media
Aseptically directly transfer a
specified volume of test
material
into culture media
Incubate for 14 days examine the media visually for growth (turbidity) at
least on
3rd, 4 th, 5 th and 8th
No microbial growth = sterile
membrane filtration
technique based on using aseptic membrane filter (pore size
not greater than 0.45 um) after filtration the
membrane filter is incubated aseptically into
appropriate media (proper temp. and time)
It is applicable for ---- aqueous solution,
--- soluble solids
---- and oils & oily solutions
Pyrogen testing
• Pyrogens = organic substances
• can removed by oxidizing them to easily eliminated gases or to nonvolatile solids
that can removed from water by fractional distillation.
Oxidizing agents = potassium permanganate + small amount
of barium hydroxide
( impart alkalinity + PPt barium salts of any acidic compd)
Test for Pyrogen The BP pyrogen test involves measuring the rise in temperature of healthy mature rabbits. The temp. is recorded after the rabbits have been IV injected with sterile solution of the test subs. 1- tools (glassware, needles, syringes free from Pyrogen) heated to 250 °C to be free from pyrogen 2- exclude any rabbit with unusual response 3- Warm product to 37 °C 4- inject into ear vein of 3 rabbits 10 ml/kg body weight) 5- record temp at 30 mins (from 90 mins before the test and to 3 hrs after injection )
If no rabbit shows any rise in temp (0.5 or more) =
product free from pyrogen
If any rabbit shows any rise in temp (0.5 or more) =
continue the test using five other rabbits
If not more than 3 rabbits show rise in temp (0.5 or more) =
or sum of 8 rabbits maximum temp = 3.3 C
the material under examination meets the
requirements for the absences of pyrogen
Parenteral quality control tests
1. Drug content and volume in container
2. Sterility test
3. Pyrogen test
4. Leaker testing and sealing verification
5. Clarity testing and particulate analysis