PROTEIN/PEPTIDE DRUG DELIVERY SYSTEM

Presented by

J.sowmya latha

m.pharm(p’ceutics)

256212886042,

MRCP.

Under the guidenceof

Mrs.yasmin begum M.pharm(ph.D)

Protein Formulations

1

• Protein sequence modification (site directed mutagenisis)

• PEGylation

2

• Proteinylation

• Microspher encapsulation

3• Formulating with permeabilizers

Site Directed Mutagenesis

E343H

Allows amino acid substitutions at specific sites in a protein

i.e. substituting a Met to a Leu will reduce likelihood of

oxidation.

Protein engneering(size,shape,etc).

PEGylation

PEG is a non-toxic, hydrophilic, FDA approved, uncharged polymer

Increases in vivo half life

Decreases immunogenicity

Increases protease resistance

Increases stability

PEGylation

+

CH

-CH

-CH

-CH

-CH

-CH

-CH

-CH

-CH

-CH

| | | | | | | | | |O

H O

HO

HO

HO

HO

HO

HO

HO

HO

H

Proteinylation

Attachment of additional or secondary (nonimmunogenic)

proteins for in vivo protection

Cross-linking with Serum Albumin

increases in vivo half life

Cross-linking or connecting by protein engineering with

antibody fragments

Proteinylation

Protein drug

+

scfc (antibody)

Formulation with permeabilizers

Salicylates (aspirin)

Fatty acids

Metal chelators (EDTA)

Drug Delivery

Route of administration

parenteral Non-parenteral

Parenteral Delivery of Proteins

• For the systemic release of the protein and peptides parenteral route is the most efficient route.

• This is the best choice to achieve the therapeutic activity.

• Mainly three types of administration are used:

Intravenous

Intramuscular

Subcutaneous

Advantages and Disadvantages

The drug carrier systems employed for defined and

controlled delivery of drug through this route are :-

particulates

Cellular carriers

pumps

• Microspheres

• Emulsions

• liposomes

• erythrocytes

• Mechanical

• Osmotic

• Controlled release

Particulates:

A)Microspheres:

These are solid spherical particles in the size range of few tenths

of micrometer to several hundreds micrometer containing

dispersed drugs in either solution or microcrystalline form.

They can be targeted to a particular organ or a specific part of a

organ o to a selective intracellular site. Passive targeting can be

achieved by cellular uptake or local injection.

Active targeting can be achieved by conjugating receptor-

specific moieties like monoclonal antibodies.

ADVANTAGES:

They can be administered subcutaneously, intramuscularly.

By using an appropriate technique they can be prepared cheaply.

DISADVANTAGES :

Drug release may be poorly defined. They have to pass successfully the biological and cellular barriers.

They may interact or form complexes with the blood

components.

B) LIPOSOMES:

• These are spherical vesicles formed when

phospholipids are allowed to swell in aqueous media.

• As their structure resembles to cell membranes,

Liposome can serves as a depot releasing the drug

slowly.

• Liposome protect the entrapped peptide from

enzymatic degradation on intravenous administration.

• They can passively deliver peptide to a particular site.

ADVANTAGES:

Flexibility in size, shape and structure. Relatively

non toxic disposition.

Ability to encapsulate both hydrophilic and

lipophilic peptide or protein.

DISADVANTAGES:

The constituent phospholipids have tendency to

interact with proteins.

Proteins susceptible to aggregation may affect the

stability of liposome.

2) CELLULAR CARRIERS:Peptides and proteins can be encapsulated in erythrocytes to

achieve their prolong release and target.

ADVANTAGES:

Biodegradability Non immunogenic Large circulation life Large

quantity of drug can be encapsulate in small volume of cell.

Offers enzymatic protection to the drug.

LIMITATION:

Long term storage is problematic.

3) PUMPS: The primary driving force for delivery is the pressure

difference .

Pressurizing the reservoir by osmotic or direct mechanical actuating can generate this difference to affect the drug release.

The pump can either be implanted or externally portable.

The ideal pump should have :

1 Wide range of delivery rate.

2 Accurate, precise and stable delivery.

3 Compatibility of drug with internal pump components.

4 Monitoring of status of pump should be easy.

5 Protection against overdose and leakage.

6 Long reservoir life.

NON PARENTERAL ROUTE OF

ADMINISTRATION

Oral Route of Administration:

oral route is most popular route from patient point of view.

Advantages:

1.Convenience

2.Acceptibility

3.High patient compliance

Disadvantages

The systemic bioavailability of protein and peptide drug by this route is generally less than 2%.

Very less permeability through oral mucosa. Potential degradation by strong acids and proteolytic enzymes.

Various strategies have been attempted for effective delivery of

proteins and peptides drugs through oral route. Some of them

are as follow:

MODIFICATION BY CHEMICAL

SYNTHESIS: • This modification assist in manipulating the pharmacokinetic

parameters to improve the therapeutic value of the parent drug.

• This can be done by:

• 1)Irreversible (analogue)

• 2)Reversible (prodrug)

Enzyme Inhibitors: Aprotinin, camostat mesylate, Bacitracin

.

Penetration Enhancer: SLS, EDTA, Fatty acids.

Carrier System : This strategy is particularly applicable in case of

poorly absorbed ,the drugs which are unstable in G.I.lumen.

Example: Liposome and sub micro emulsion

Buccal Route of Administration

The drugs are absorbed through oral mucosa i.e. occur in non

keratinized sections.

ADVANTAGES:

1)It is close resemblance to oral route seems well acceptable to

the patients.

2)Can attached and remove without any pain or discomfort.

3)It is worth considerable when penetration enhancers are

used.

The inherent problem with these dosage form is the risk of drug loss

by accidental swallowing leads to less administration time.

The various strategies employed for Buccal delivery:

1)Adhesive tablets

2)Adhesive gels

3)Adhesive patches

4)Absorption promoters

Nasal Route of Administration

The nasal route has been chiefly employed for producing local action on mucosa.

This mucosa is more permeable compare to the oral mucosa.

The nasal absorption of protein and peptide can be via special diffusion and special targeted mechanism i.e. 1-20%

Example: Insulin and Human growth hormone.

Advantages:

Convenient ,simple and practical way of drug administration.

High vascular permits better drug absorption. First pass metabolism can be avoided. Rapid onset of action.

Disadvantages:

Long term usage causes toxicity.

Enzymatic barrier, size of protein and peptide drug reduce the systemic bioavailability.

•

Number of approaches are available for achieving effective

delivery of protein and peptide drug. Those are:

VISCOSITY MODIFICATION

Eg:Hydroxy propyl methyl cellulose

MEMBRANE TRANSPORTER

Eg:Surfactant( SLS)

ENZYME INHIBITOR

Eg:Bestatin, Amastatin pH MODIFICATION Insulin exhibit

highest solubility in acidic medium

TRANSDERMAL ROUTE OF

ADMINISTRATION

This is a topical medication.

In this the drug is absorb through skin. Example: Insulin,

Vassopressin.

ADVANTAGES :

Better and improved patient compliance.

Drug with short half life can also administer.

Administration of drugs with low therapeutic index.

Controlled administration is possible.

DISADVANTAGES:

Low rate of permeation of these drugs because of large molecular

weight.

High lipophilicity and hydrophilicity of stratum corneum of skin.

Number of approaches are available for achieving effective

delivery of protein and peptides. Those are:

1)IONOPHORESIS: induces migration of ions or charged

molecules when the current is allowed to flow through an

electrolyte medium.

2)PHONOPHORESIS: thermal effect of ultrasonic waves

alters the physical structure of skin and enhance permeability.

3)PENETRATION ENHANCER: Oleic acid and Surfactant.

4)PRODRUG: Modification in the ph ysiochemical properties

of drug like lipophilicity and charge will enhance the

permeability of the drug.

PULMONARY ROUTE OF

ADMINISTRATION

o Respiratory track offers an alternative site for systemic non

invasive delivery of protein and peptide drugs Alveoli and lungs

are the absorption site(90%).

o Drugs are absorbed through lungs by simple diffusion and carrier

mediated transport.

ADVANTAGES:

Provide a direct route to systemic circulation.

Safe route even in patient with lungs disease.

Decrease in dose requirement.

Fast absorption. Patient compliance.

RECTAL ROUTE OF ADMINISTERATION

Rectum is highly vascularised body cavity. The rectal mucosa is

devoid of any villi.

These drugs are in the form of gel and dry powders.

Example: Insulin, Gastrin and Calcitonin.

ADVANTAGES:

Large dose can be administer.

Avoid first pass metabolism.

DISADVATAGES:

Only small amount of drug can be administered.

Inflammation and edema can be observed.

Degree of bioavailability is less due to presence of hydrolytic

enzymes in lungs. Most of the drug administer at upper part of

the lung area with low systemic circulation.

Occular route of administration

To treat infections and enzymes used to promote wound healing.

a. Bacitracin

The drug is applied topically to the eye for a variety of

conditions, including eyelid burns and corneal superficial

punctate keratits .It is also used to treat optic neuritis.

Commercial bacitracin is a mixture of at least nine bacitracins,

which is used for its antibacterial activity

b. Chymotrypsin

Chymotrypsin is used clinically in the eye for enzymatic

intracarpsular lens extraction.

c. Cyclosporine

Cyclosporine are a group of biologically active metabolites

produced by Fungi. When cyclosporine A is administered by

nonocular route in rats, it produces significant blood levels, but it

can not be detected in tissues.

Advantages

The mode of delivery is convenient, i.e., eye drops.

Systemic absorption is extremely rapid.

Avoid first-pass metabolism.

The formulation can be designed to prolong drug action

and/or reduce drug concentrations to achieve consistent drug

action with least side effects.

Drug delivery can be controlled precisely.

Vaginal route of administration

The vaginal preparations currently on the market contain topicaly effective agents.

Anti-microbial agents:eg;metronidazole

Estrogenic steroids such as estroidal for restoring the normal physiology of vaginal mucous.

Advantages:

The feasibility of self administration

The possibility of prolonged retention of drug delivery system.

The potential avoidance of hepato gastro intestinal first pass elimination.

Minimizatio of proteolytic degradation.

Recent advances in protein drug delivery

Polymeric drug delivery

Microencapsulation

Polymer scaffolds

Magnetic targeted carrier

Liposomes

Hydrogel based drug delivery

Polymeric drug delivery

Frequency of doses reduced

Drug utilised more effectively

Drug stabilised inside the polymeric matrix

Reduced side effects

Possibility of dose dumping

Deactivation of drug inside the polymer

Release Mechanism

Diffusion of drug out of the polymer

o o o

o o o

o o o

o

o o o

o o

Drug Release by Polymer

Degradation

Hydrolysis

Enzymatic (Phosphotases;

Proteases etc.)

Microsphere Drug delivery

• Process involves encapsulating protein/peptide drugs in small

orous particles for protection from “insults” and for sustained

release.

Release mechaism:

• Hydrophyllic(i.e gelatin)

-best for burst release

Hydrophobic(i.e PLGA):

-good sustained release(esp vaccines)

-tends to denature proteins.

Hybrid (amphaphatic):

-good sustained release

-keeps proteins native/active

Microsphere Drug delivery

• Two types of microspheres

Nonbiodegradable

e.g, ceramic particles

polyethylene co-vinyl acetate

polymethacrylic acid/PEG

Biodegradable (preferred)

e.g, gelatin

polylactic-co-glycolic acid

(PLGA)

Polymer scaffolds

Incorporate drug in to polymer matrix.

Protection of drug from enzymatic degradation particularly

applicable to protein and peptide drugs.

Release drug at knwn rate over a prolonged duration.

Drug dispersed or dissolved in suitable polymer.

Diffusion of drug through pores of polymer.

Magnetic Targeted Carriers (MTCs)

Microparticles, composed of

elemental iron and activated

carbon

Drug is adsorbed into the

MTCs and transported

The particles serve as delivery

vehicles to the area of the tumor

for site-specific targeting

Liposomal Drug Delivery

Spherical vesicles with a phospholipid bilayer

E.g, Bleomycin encapsulated in

thermo sensitive liposome enhanced

antitumor activity and reduced normal

tissue toxicity.

s.C injection of –vely cherged liposomes

produced a prolonged hypoglycemic

effect in diabetic dogs.

Liposome have recently been used

successfully as vehicles for vaccines.

Hydrogel Based Drug Delivery

Hydrogels are three dimensional networks of hydrophilic

polymers that are insoluble

Hydrogel Based Drug Delivery

R

O

N N

O

R

H H

R = polymer backbone

R

O

NH2

+O

HH

H2O

Hydro gels can swell as a result of changes in pH,

Temperature.

e.g Insulin,it has been incorporated in hydro gels and

investigated by researches effectively.

conclusion

Protein and peptide pharmaceuticals are very important class

of therapeutic agents.

Their emergencies on the clinical & therapeutic horizon has

intensified the investigation for their convenient & effective

delivery through noninvasive route.

The additional challenges for the pharmacist is the designing

& development of viable delivery system for non parenteral

administration of protein and peptide drugs.

References

• Novel drug delivery systems,second edition,reviced and expanded,YIE CHIEN,pg no;631 to 723

• Controlled drug delivery systems concepts and advances by S.P.VYAS,ROOP K.KHAR(controlled protein delivery pg no:503 to 566.

• Robinson, R. Joseph. Controlled Drug Delivery : Fundamental &application, Second edition, MercelDekkar, USA, pg no:7-14.

• Jain N.K., Progress in Controlled & novel Drug delivery system. CBS publication; Delhi, 195.

• Gupta H, Sharma A. Recent trends in protein and peptide drug delivery systems. Asian J Pharm 2009;3:69-75.