1. Polymeric Sciences Dr. Basavaraj K. Nanjwade M. Pharm., Ph. D
Department of Pharmaceutics
Faculty of Pharmacy
Omer Al-Mukhtar University
Tobruk, Libya.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

2. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
CONTENTS
Definition and Types of polymers.
Properties of Polymers.
Drug-Polymer Interactions.
Polymers in Pharmaceutical preparation.
Viscosity of polymer solutions.
References.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

3. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Introduction
Polymers are used extensively in our daily routine life.
In pharmaceutical preparations also they have several applications
e.g. In manufacturing of bottles, syringes, vials, catheters, and also in drug formulations.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

4. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Definition
“Polymer” word is derived from Greek roots “Poly” meaning many and “Meros” meaning parts.
Definition :
Polymers are long chain organic molecules assembled from many smaller molecules called as monomers.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

5. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Definition
Copolymer :
Polymers formed from two or more different monomers are called as copolymers.
- [A – B – A – B – A – B] –
Homopolymer :
Polymers formed from bonding of identical monomers are called as homopolymers.
- [A – A – A – A – A] -
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

6. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Types of polymers
A. Based on origin :
a) Natural Polymers :
e.g. Proteins – Collagen, Keratin, Albumin
Carbohydrates – starch, cellulose, glycogen.
b) Synthetic Polymers :
e.g. polyesters, polyanhydrides, polyamides.
B. Based on Bio-stability :
a) Bio-degradable Polymers :
e.g. polyesters, proteins, carbohydrates, etc
b) Non – biodegradable Polymers :
e.g. ethyl cellulose, HPMC, acrylic polymers, silicones.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

7. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Types of polymers
C. Based on Reaction mode of Polymerization : a) Addition Polymers: Here, the monomer molecules bond to each other without the loss of any other atoms. e.g. Alkene monomers b) Condensation Polymers: Usually two different monomers combine with the loss of small molecule, usually water. e.g. polyesters, polyamides.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

8. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Types of polymers
D. Based on Interaction with Water :
a) Non – biodegradable Hydrophobic Polymers :
These are inert compounds and are eliminated intact from the site of application.
e.g. polyethylene – vinyl acetate, polyvinyl chloride.
b) Hydrogels :
They swell but do not dissolve when brought in contact with water.
e.g. polyvinyl pyrrolidone
c) Soluble Polymers :
These are moderate mol. wt uncross-linked polymers that dissolve in water.
e.g. HPMC, PEG
d) Biodegradable Polymers :
These slowly disappear from the site of administration in response to a chemical reaction such as hydrolysis.
e.g. Polyacrylic acid. Polyglycolic acid.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

9. Properties of Polymers
Should be inert and compatible with the environment.
Should be non-toxic.
Should be easily administered.
Should be easy and inexpensive to fabricate.
Should have good mechanical strength
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

10. Properties of Polymers
It must be soluble and easy to synthesize; must have a finite molecular weight.
Should provide drug attachment and release sites for drug polymer linkages.
Should be compatible with biological environment, i.e. non-toxic and non-antigenic.
Should be biodegradable or be eliminated from body after its function is over.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

11. Drug-Polymer Interactions
Biodegradable polymer for ocular , nonviral DNA , tissue engineering , vascular , orthopedic , skin adhesive & surgical gloves.
Biodegradable polymer lens materials that could ensure the proper delivery of medicine for treating glaucoma, chronic dry eye, corneal ulcers and other ocular ailments.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

12. Polymers in Pharmaceutical preparation
Tablets :
- As binders
- To mask unpleasant taste
- For enteric coated tablets
Liquids :
- Viscosity enhancers
- For controlling the flow
Semisolids :
- In the gel preparation
- In ointments
In transdermal Patches
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

13. Polymers in Pharmaceutical preparation
Reservoir Systems
- Ocusert System
- Progestasert System
- Reservoir Designed Transdermal Patches
Matrix Systems
Swelling Controlled Release Systems
Biodegradable Systems
Osmotically controlled Drug Delivery
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

14. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
A. Reservoir System :
Ocusert System :
- Novel means of controlled ocular drug delivery
- Used for max 7 days treatment of Glaucoma
- Consists of core reservoir of pilocarpine & alginic acid sandwiched between two sheets of transparent, lipophillic, rate controlling membrane of ethylene-vinyl acetate copolymer.
- Inserted in cul-de-sac, lachrymal fluid enters the system and the dissolved drug slowly gets released through polymeric membrane.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

15. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
A. Reservoir System :
Progestasert system :
- Used for once-a-year contraception
- Consists of drug saturated liquid medium
encapsulated in a polymeric membrane.
- Progesterone is released at a constant rate of 65
µg/day.
- Polymers used are : Silicone elastomers,
polyethylene, ethylene-vinyl acetate.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

16. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
A. Reservoir System :
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

17. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
A. Reservoir System :
Transdermal Patches :
- Drug is sandwiched between drug impermeable backing and drug permeable rate controlling polymer.
e.g. Ethylene-vinyl acetate copolymer
- In the reservoir, drug is dispersed in solid polymer matrix.
e.g. Polyisobutylene
- On the external surface, there should beadhesive polymer.
e.g. Silicone Polymer, Polyacrylates.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

18. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Transdermal Patches :
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

19. B. Osmotically Controlled Drug Delivery System
Drug is coated with semi-permeable polymer
e.g. Cellulose acetate.
Water generates osmotic pressure gradient by permeating through semi-permeable membrane.
Due to that drug pumps out of delivery orifice over a prolonged time at a defined rate.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

20. C. Biodegradable System
Mainly used for parenteral controlled drug delivery.
Drug is encapsulated in biodegradable microcapsules which are suspended in aqueous / oleaginous medium and injected subcutaneously or intra-muscularly.
Polymers used for microcapsules are :
Gelatin, dextran, polylactate, lactide–glycolide copolymer.
The release of drug is controlled by the rate of bio-degradation of polymer.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

21. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
D. Matrix Systems
Drug particles are enclosed in a matrix environment formed by cross-linking of polymer chains.
For the drug to get released, it has to be first dissolved in surrounding polymer and then diffuse through the polymer structure.
Polymers used are :
polyalkyls, polyvinyls, etc.
Example – Nitroglycerine releasing system for prophylaxis or treatment of angina pectoris.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

22. E. Swelling Controlled Release Systems
Drug is enclosed in a collapsible drug compartment inside a rigid, shape-retaining housing.
The shape between external housing and drug compartment contains laminate of swellable, hydrophillic cross-linked polymer.
e.g. polyhydroxyalkyl methacrylate.
This polymer absorbs GI fluid through annular openings in the bottom of housing.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

23. Biodegradable Polymers
Definition :
Biodegradable polymers are defined as polymers comprised of monomers linked to one another through functional groups and have unstable links in the backbone.
They slowly disappear from the site of administration in response to a chemical reaction such as hydrolysis.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

24. Biodegradable Polymers
Synthetic Polymers :
a) Aliphatic polymers
b) Polyphospho-esters
c) Polyanhydrides
d) Polyorthoesters
Natural Polymers :
a) Collagen
b) Albumin
c) Casein
d) gelatin
Environment Responsive Polymers :
a) Thermo sensitive – Poly acryl amide
b) pH sensitive – Methyl vinyl ether
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

25. Mechanism of Biodegradation
A. Hydrolytic Degradation :
Breakdown of polymer by water by cleaving long chain into monomeric acids. This is done by two ways :
Bulk eroding polymers
e.g. Polylactic acid (PLA)
Polyglycolic acid (PGA)
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

26. Mechanism of Biodegradation
Surface Eroding Polymers :
e.g. Polyanhydrides
B. Enzymatic Degradation :
Exact mechanism is not known but may be due to lysis of long polymer chain by attaching to it.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

27. Biodegradable Polymers
Factors affecting Biodegradation :
- Polymer morphology
- pH & ionic strength
- Drug – polymer interaction
- Chemical composition and structure
Applications :
- Sutures used during the surgery
- For orthopaedic applications
- For tissue regeneration
- For protein drug delivery
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

28. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Natural Polymers
Natural polymers remains the primary choice of formulator because
- They are natural products of living organism
- Readily available
- Relatively inexpensive
- Capable of chemical modification
Moreover, it satisfies most of the ideal requirements of polymers.
But the only and major difficulty is the batch- to-batch reproducibility and purity of the sample.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

29. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Natural Polymers
1) Proteins :
- Collagen : Found from animal tissue.
Used in absorbable sutures, sponge wound
dressing, as drug delivery vehicles
- Albumin : Obtained by fabrication of blood from healthy donor.
Used as carriers in nanocapsules & microspheres
- Gelatin : A natural water soluble polymer
Used in capsule shells and also as coating
material in microencapsulation.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

30. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
Natural Polymers
2) Polysaccharides : - Starch : Usually derivatised by introducing acrylic groups before manufactured into microspheres. Also used as binders. - Cellulose : Naturally occuring linear polysaccharide. It is insoluble in water but solubility can be obtained by substituting -OH group. Na-CMC is used as thickner, suspending agent, and film formers. 3) DNA &RNA : They are the structural unit of our body. DNA is the blueprint that determines everything of our body.
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

31. Viscosity of polymer solutions
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

32. Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.
References
Novel drug delivery systems - Y. W. Chien-Dekker 50
Bio–adhesive drug delivery system-Dekker 98
Encyclopedia of controlled drug delivery systems.
Controlled release of biologically active agents- Richard baker
Polymer in control drug delivery edited by Lisbeth Lillum and Stanley S. Davis
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.

33. E-mail: nanjwadebk@gmail.com
THANK YOU
2014/01/26
Faculty of Pharmacy, Omer Al-Mukhtar University, Tobruk, Libya.