1. SEMINAR ON
POLYMER SCIENCE
SUBMITTED TO :
DR. R. V. KULKARNI
(M.PHARM, Ph.D)
SUBMITTED BY:
ROSHNIKUMARI PATEL
1ST YEAR M.PHARM
DEPT. OF PHARMACEUTICAL TECHNOLOGY
2014-2015

2. CONTENTS:
 INTRODUCTIO
 POLYMER CLASSIFICATION
 APPLICATION OF POLYMER IN
FORMULATION OF CONTROLLED DRUG
DELIVERY SYSTEM
 BIODEGRADABLE AND NATURAL POLYMER

3. ITRODUCTION:-
The word polymer is derived from greek
word
“Poly” means “many”
“Meros” means “parts”.
The basic unit is known as monomer.

4. Definition:
Polymer is composed molecule with
large molecule mass, composed of repeating
structural units or monomers connected by
covalent chemical bonds.
The process used for this is known
as “polymerization”.

5. IDEAL CHARACTERISTICS :
Should be inert.
Should be compatible with environment.
Should be non toxic.
Easy and inexpensive to fabricate dosage
form.
Should have good mechanical strength.
Should be inexpensive.

6. Factors that affects physical properties of
polymer:
Degree of polymerization
Molar mass distribution.
Crystallinity.
Branching.
Stereo regularity : isoelectric arrangement of
function group of backbone of carbon skeleton.
Strength may vary with temperature and
formulation.

7. POLYMERIZATION:
The use of heat , pressure or a chemical catalyst to link
monomer material into polymer chain.
Polymerization is a process of linking of small molecule
together .
These small molecules are called monomers.

8. These monomer are linked together in different ways to
form:
Linear polymers
Branched polymer
Cross linked polymer
Linear polymer or branched polymer :
They are also known as thermoplastic materials.
They flow when heated .
They can be fabricated by the application of heat and
pressure.
They are soluble in certain solvents.
Example: Polyesters, polyamides, etc

9. Cross linked polymers:
They are also known as thermosetting polymer.
They do not flow when heated .
They can not be fabricated by the application heat and
pressure.
Since all the polymer chain are interconnected by the
covalent cross links these polymers can not be dissolved and
only swell to the extent allowed by the cross linked density.
Example : Bakelite, phenol formaldehyde polymers, resins,
urea formaldehyde polymer.

11. Classification of polymers:
Polymers are classified based on :
•Depending on the way by which monomer are linked
•Method of polymerization
•Mechanism of polymerization
•Origin of polymer
•Degradability of polymer
•Based on composition
1. Depending on the way by which monomers are linked:
•Linear polymer
•Branched polymer
•Cross linked polymer
2. Based on composition:
•Homo polymer
•Co polymer

12. 3. Method of polymerization:
Addition polymer
Condensation polymer
4. Mechanism of polymerization:
Chain polymerization
Step growth polymerization
5. Origin of polymer:
Natural polymer
Semi-synthetic polymer
6. Degradability of polymer:
Synthetic polymer
Biodegradable polymer
non Biodegradable polymer

13. METHOD OF POLYMERIZATION:-
Here the polymers are classified depending upon the method of
polymerization:-
•Addition polymers
•Condensation polymers
ADDITION POLYMERS:-
•In this the repeating units of the polymers have the same
molecular formula as the monomers.
These are prepared by the polymerization of the monomers
bearing one or more double or triple bonds or by the ring
opening reactions of the cyclic structures
E.g. Low Density Polyethylene(LDPE), High Density
Polyethylene(HDPE),Poly Vinyl Chloride (PVC),Poly Styrene
(PS), Poly Tetra Fluoro Ethylene (PTFE or TEFLON),Poly
Vinyl Acetate (PVAc) etc

15. CONDENSATION POLYMERS:-
These are formed by the successive reactions of the
functional groups.
Since the by-product formed is a smaller molecule, the
repeating units of the polymers have fewer atoms than the
monomers.
Examples: Polyesters like Dacron, Mylar etc. Polyamides
like Nylon 6, Nylon 66, Perlon , Kevlar, Nomex etc.
Polyurethanes like Spandex etc.

16. Polyamide: Nylon

17. Based on composition:
Homopolymer:
Eg: polythene
Polystyrene
Like a-a-a-a
Copolymer :
Eg: silicon
Ethyl cellulose
Like a-b-a-b-a-b
MECHANISM OF POLYMERIZATION:-
Here the polymers are classified depending upon the
mechanism by which they are formed:
•Chain (Addition) polymerization
•Step growth (Condensation )polymerization

18. CHAIN (ADDITION)POLYMERIZATION:-
•In this the polymerization reaction proceeds via discrete
initiation, propagation and termination steps.
•Once the polymerization stars, each polymer chain
undergoes rapid preferential growth in terms of molecular
weight with a steady decrease in monomer concentration.
Examples: Vinyl polymers were probably the first to be
synthesized in this manner, when in 1839 Simon reported
the conversion of styrene to some gelatinous mass, Low
Density Poly Ethylene (LDPE), High Density Poly Ethylene
(HDPE), Poly Vinyl Chloride (PVC), Poly Styrene, Poly
Tetra Fluoro Ethylene (PTFE or TEFLON), Poly Vinyl
Acetate (PVAc) etc.

20. There are several different techniques of synthesis
depending on the active site. These are:
Active site Synthesis technique
Free radicals Free radical polymerization
Carbanions Anionic polymerization
Carbonium ions cationic polymerization
Coordination bonds with
transition metals
Ziegler-natta polymerization

21. STEP GROWTH (CONDENSATION)
POLYMERIZATION:-
In this there are no discrete initiation, propagation,
termination steps
Here the reaction proceeds via specific reactions between
the functional groups and thus any two molecular species
with appropriate group react.
The molecular weight of the polymer increases steadily
throughout the reaction and monomer disappears early in the
reaction.
Examples: Polyesters like Dacron, Mylar etc. Polyamides
like Nylon 6, Nylon 66, Perlon, Kevlar,Nomex etc.
Polyurethanes like Spandex etc.

22. KEVALAR
NOMEX
SPANDEX

23. ORIGIN OF POLYMERS:
Here the polymers are classified depending upon their
origin.
Natural polymers:
Example: Gelatin, Collagen etc.
Semi synthetic polymers:
Example: EC,HEC, HPMC,HPC etc.
Synthetic polymers:
Example: PGA, PLA etc.

24. DEGRADABILITY OF POLYMERS:
Here the polymers are classified depending upon their ability
to degrade.
•Biodegradable polymers: Example: Natural polymers like
gelatin, collagen etc and Synthetic polymers like PGA, PLA
etc.
•Non-biodegradable polymers: Example: Semi synthetic
polymers like EC, HEC, HPMC, HPC etc.
Importance:
•Polymers are used as carrier materials in the formulation of
controlled drug delivery systems.
•The selection of the polymer depends upon the intended use
and the desired release profile.

25. BIODEGRADABLE POLYMERS:
These are polymers consisting of monomers
linked to one-another through functional groups and
have unstable linkages in their backbone.
These polymers are biologically degraded or eroded
into oligomers or monomers that can be metabolized and
excreted :
 By the enzymes introduced in-vitro(or)
By the enzymes generated by surrounding living
cells(or)
By the enzymatic process.

26. There are three basic approaches which govern the design
of controlled drug delivery systems containing bio-degradable
polymers:
Erosion of the polymer surface with concomitant release
of the physically entrapped drug.
Cleavage of the covalent bond between the polymer and
the drug, occurring at the polymer bulk or at the surfaces
followed by the diffusion drug release.
Diffusion controlled release of the physically entrapped
drug, with bio absorption of the polymer delayed until drug
depletion.
These polymers are applicable to a wide range of drugs.

27. Ideal characteristics of Biodegradable
polymer:-
They should be biocompatible-(shape, surface, and
leachable)
They should be bio absorbable-(degradability profile,
reabsorption of degradation products.)
They should be bifunctional-(physical, mechanical and
biological).
They should be stable-(processing, sterilization and
storage).

28. Mechanism of release through biodegradable
polymers:
Diffusion
Swelling
Erosion

29. CLASSIFICATION OF BIODEGRADABLE
POLYMERS:
•Natural polymers:
Proteins: Example: Albumin, Collagen, Gelatin etc.
Polysaccharides: Example: Sodium alginate, Chitin,
Chitosan, Cellulose, Dextran, Insulin, Hyaluronic acid,
Starch
•Synthetic polymers:
Aliphatic polyesters: Example: Poly-Glycolic Acid
(PGA), Poly Lactic Acid (PLA), Poly-Hydroxy Butyrate
(PHB), Poly-β-Malic Acid (PMA) etc.
Poly Phospho Esters
Poly Anhydrides
Poly Phosphazenes
Pseudo Amino Acids
Poly Ortho Esters

30. NATURAL POLYMERS:-
The use of natural biodegradable polymers to deliver
drugs continues to be an area of active research despite
the advent of synthetic biodegradable polymers.
Natural polymers remain attractive primarily because,
They are an attractive class of biodegradable polymers.
They are derived from natural sources.
They are easily available.
They are relatively cheap.
They qualify for a number of chemical modifications.
They can be a protein or a polysaccharide in chemical
origin.

31. Modified natural polymers are natural polymers altered to
improve their biodegradation profile that can be achieved
by chemical modifications or enzymatic alteration.
Examples:
Proteins:
•Albumin
•Collagen
•Gelatin
ALBUMIN:
It is a major plasma protein component.
It accounts for more than 55% of total protein in human
plasma.
It is used to design particulate drug delivery systems.

32. SERUM ALBUMIN AND ALBUMIN:-

33. Advantages:
It is easily available.
It is biodegradable into natural products.
Non-toxic and non-antigenic.
The release pattern of drugs from albumin micro-spheres
is biphasic initial burst release is followed by a
comparatively slower first order release.

34. Factors affecting drug release from albumin
micro-spheres:
Physicochemical properties and the concentration of the
drug.
Interaction between the drug and the albumin matrix.
Size and density of microspheres.
Nature and degree of cross-linking.
Presence of the enzymes and pH of the environment.

35. Uses:-
Albumin micro-spheres are used to deliver drugs
like Insulin, Sulphadiazene, 5-fluorouracil,
Prednisolone etc.
It is mainly used in chemotherapy, to achieve high
local drug concentration for relatively longer time.

36. Collagen:-
It is the primary structural protein.
It occurs in the animal tissue as aligned fibres in
skin, connective tissue and the organic substances of
the bone.

37. Advantages:
It is easy to isolate and purify in large quantities.
It is biocompatible and non-toxic.
It has well established physicochemical, structural and
immunological properties.
It is easy to process collagen in various forms.
Disadvantages:
Poor stability.
Variation in drug release kinetics.
Low mechanical strength and elasticity.
To overcome poor mechanical properties and non-reproducible
delivery rates of collagen, collagen shields
(which look like the contact lens) are prepared from
intact porcine sclera tissue. They are spherical in shape,
having a thickness of 0.027mm-0.071mm.

38. Uses:
Collagen shields are used in the ocular
drug delivery system of drugs like Pilocarpine,
Gentamycin etc.

39. Gelatin:
It is a heterogeneous product obtained by irreversible
hydrolytic extraction of treated animal collagen.
This converts tough fibrous collagen into a water soluble
protein.
The physicochemical properties of gelatin are dependent
on the source of collagen, the extraction method, pH value,
thermal degradation and electrolyte content.
Advantages:
It is easily available.
It has low antigenic profile.
It binds poorly to the drug molecules.
It reduces the chances of drug degradation as low
temperature is used for the preparation technique.

40. Uses:
It is used as a matrix and as a coating material
in drug delivery systems.
Gelatin micro-pellets can be prepared for oral
controlled drug delivery systems.
Polysaccharides:
Sodium alginate
Chitin
Chitosan
Dextran, etc.

41. Sodium alginate:
Alginates are hydrophilic carbohydrates obtained from
various species of brown sea weeds, by the use of dilute
alkalies.
They can be easily fabricated into particulate systems.

42. Advantages:
Since the use of organic solvents and high
temperature is not required even viable bacteria and
viruses can be employed.
It protects the antigen and the vaccines against
degradation in GIT.
It acts as an adjuvant.
Uses:
Alginates are particularly used as carriers of peptides
and other sensitive drug molecules since particulate
carriers can be easily prepared in aqueous solution at
room temperature.
Alginate micro-spheres are efficiently used for oral
delivery of vaccines.

43. Chitin:
It is a linear poly-cationic polymer of N-acetyl-D-glucosamine
units linked by β-D (1-4) bonds.
It is insoluble in common solvents.
It has low chemical reactivity.
Industrial sources of chitin are: shells of lobster shrimp
and crab.
Chitosan:
It is a principle derivative of chitin and is obtained by
alkaline deacetylation.
Both chitin and chitosan are distinguished by their
solubility profile in dilute aqueous acid solutions.
Drug diffusion from chitosan matrix can be controlled
by employing a cross-linking agent like glutaraldehyde

44. Characteristic properties of chitosan:
It has antacid, antiulcer, hypocholesterolemic and wound
healing properties.
Haemostatic and spermicidal properties owing to its ability
to bind strongly with the mammalian cells by the virtue of
their poly-cationic character.
Presence of reactive functional group and cationic
character opens up possibilities for their application in
controlled drug delivery systems.
It is biodegradable, biocompatible and non-toxic.
It has gel forming ability at low pH and so is a suitable
polymer for oral sustained release drug delivery system.
The chitosan matrix formulation floats and gradually
swells in acidic medium.
It also has an antitumor activity and so is used for the
treatment of cancer.

45. Factor affecting drug release from chitosan
micro-spheres:
Particle size and density of micro-spheres.
Nature and degree of cross-linking.
Physicochemical properties and the concentration of
the drug.
Type of chitosan.
Viscosity of lipophilic phase.

46. Uses:
It is used as directly compressible excipient.
It is used to decrease the angle of repose and hence
improve the flow properties of conventional excipients like
mannitol, starch, lactose etc.
It is used as a diluent, binder, lubricant and a potential
disintegrant due to its water uptake properties.
Ulcerogenic drugs like aspirin can be effectively
administered with chitosan as it has a gel forming property at
low pH and also has antiulcer and antacid properties.
It is used to reduce the gastric mucosal injury associated
with Diclofenac sodium.

47. It interacts with liposome and results in:
Liposome Stabilization.
Imparts targeting potential to the Liposome owing to
its Mucoadhesive property
Chitosan 5-fluorouracil conjugates have lower side
effects than native 5-fluorouracil.
The film forming ability of chitosan can be employed
for the development of contact lenses.
It is also used in ocular bandage lenses, which is used
as a protective device for acute or chronic traumatic
eyes.

48. Dextran:
It is a polymer of glucose.
It is prepared by subjecting the sucrose to the action
of the bacterium Leuconostoc mesenteroides.
The crude high molecular weight Dextran which is
formed is hydrolyzed and fractionated to yield Dextran
of desired molecular weight.
. It is used in the form of a gel for colonic delivery of
drugs

49. Synthetic polymers:
Most attractive class of polymers.
Biocompatible and versatile in terms of physical,
chemical and biological properties.
Examples:
Aliphatic polyesters: PGA, PLA etc.
poly Phospho Esters (PPE)
Poly Ortho Esters (POE), etc.

50. PGA and PLA:
They are also known as poly-glycolic acid and poly-lactic
acid respectively.
They are the simplest linear aliphatic polyesters.
The copolymers of glycolic acid and both L-Lactic
acid and DL-Lactic acid are used for the development of
drug delivery systems.
The in-vitro degradation profile is determined by the
water uptake capacity and the crystallinity of the
polymer.
The rate of hydration and subsequent degradation can
be increased by increasing the glycolic acid ratio and the
lactic acid ratio in the copolymer respectively.
Solubility of polymers in common solvents is of prime
importance while formulating delivery systems.

51. Poly-glycolic acid and glycolic acid rich copolymers
are insoluble in most organic solvents except highly
fluorinated organic solvents like Hexafluoroisopropanol.
Homo-polymers based on D-, L- and DL-Lactic acids
are soluble in dioxane, ethyl acetate, halogenated
hydrocarbons and tetrahydrofuran,
Poly-lactic acids offer broad spectrum activity and
versatility by changing:
Monomer stereochemistry
Co-monomer ratio
Polymer chain linearity
Polymer molecular weight

52. Biodegradation:
PGA/PLA chains are cleaved by hydrolysis to form
monomeric acid units.
They are eliminated in-vivo through Krebs ‘cycle as
CO2 and in urine.
PGA/PLA on hydrolysisGlycolic acid /Lactic
acidKrebs’s cycle CO2+Excreted in urine.

53. Formulation Techniques:
PGA/PLA micro-spheres can be prepared by:
Solvent evaporation
Phase separation
Fluidized bed coating
Implants can be prepared by:
Compression moulding
Injection moulding
Screw extrusion method
Precaution:
First dry the bulk polymer and the bioactive drug at ambient
temperature under vacuum prior to processing.
The process equipment must be covered with dry N2
blankets.

54. Drug release from the polymer:
Leaching of the contents from the polymer.
Bio-erosion of the matrix.
Poly-phospho esters:
1. These are referred to as polyphosphates,
polyphosphonates or polyphosphates depending upon the
nature of side chain attached to phosphorus.
2. These polymers are:
•Versatile
•Have good physicochemical profile
•Biocompatible
3.These polymers are used to deliver paclitaxel and
cisplatin in the form of micro-spheres.

55. Poly-ortho esters:
•These polymers have acid-sensitive linkages in their
backbones and allow easy manipulation of hydrolysis rate
by physical incorporation of acidic or basic excipients into
the matrix.
•The hydrolysis of these polymers is predominantly
confined to the outer surface and the resultant surface
erosion allows excellent control of the release of the
incorporated therapeutic agent.
•Hydrolysis takes place via initial protonation of alkoxy
oxygen followed by bond cleavage involving exocyclic or
endocyclic alkoxy group.
•Since these are acid sensitive and are stable in base control
over erosion can be achieved by:
•Use of an acidic excipients to accelerate rate of
hydrolysis (or)

56. Use of a base to stabilize the interior of the device.
 These are prepared by trans-esterification.
 Implants and oral drug delivery systems can be
developed
Non-Biodegradable Polymers:
Examples:
•Ethyl cellulose
•Hydroxyl Propyl Methyl Cellulose
•Ethylene Vinyl Acetate
•Poly-ethylene oxide, etc.

57. Applications of polymer in formulation of
controlled drug delivery system:
ORAL DRUG DELIVERY SYSTEM
TRANDERMAL DRUG DELIVERY SYSTEM
OCCULAR DRUG DELIVERY SYSTEM
OTHER APPLICATION

58. 1.ORAL DELIVERY SYSTEM:
Here the drug gets released at controlled rate when
administered orally. for that several mechanisms are involved.
•Osmotic pressure controlled GI deliver system.
•Gel diffusion controlled GI delivery system
•Mucoadhesive GI delivery system
•Osmotic Pressure Controlled delivery
system:
Semi permeable membrane made from biocompatible
polymers
e.g. cellulose acetate
•Gel diffusion controlled delivery system:
Fabricated from gel forming polymers
e.g. CMC.
•Mucoadhesive drug delivery system:
It is capable of producing an adhesion interaction with
a biological membrane.
e.g. carbopol.

59. 2.TRANSDERMAL DRUG DELIVERY
SYSTEM:
Mostly used when the medicaments are applied
on
topical route. It is easily removable when
termination
of treatment is needed or else in case of condition
of
toxicity is seen.
e.g. Transdermal patch of scopolamine, nitro
glycerin

61. 3. OCULAR DRUG DELIVERY SYSTEM:
It allows prolonged contact of drug with corneal surface
of eye.
 Highly viscous suspension and emulsion are served to
have such purpose but these preparations don’t achieve
this purpose at a controlled rate.
Many ocular drug delivery formulations developed which
continuously release the drug at a controlled rate
The best example is ocular insert/ocusert
developed to delivered pilocarpine in the
treatment of glaucoma

62. Example of pilocarpine ocusert

63. 4.Other applications:
Drug Delivery and the Treatment of
Diabetes: Here the polymer will act as
Barrier between blood stream and insulin
example of polymer- N,N-dimethylaminoethylmethacrylate
or polyacrylamide.

65. Drug delivery of various contraceptives
and hormones:
Example: Medroxy progesterone acetate releasing
vaginal contraceptive rings

66. Polymers can be used as film-coatings to disguise
the unpleasant taste of a drug to enhance drug stability
and to modify drug release characteristics.
Lactic acid and glycolic acids are widely used in
drug delivery research due to their versatility in
polymer properties.
Poly-anhydrides are used in CDDS because of their
unique property of surface erosion.
Poly-caprolactone is used with other polymers in
designing CDDS.
Poly-phosphazenes are used in the formulation of
Melfalan matrix systems.
Pseudo-amino acids are used in controlled release
formulations.
Hyaluronic acid is used in controlled release
ophthalmic preparations

67. Various uses of polymer in
pharmaceutical sciences:
 Formulation of matrix tablets
 Formulation of nanoparticles
 Formulation of solid dispersion
 In targeted drug delivery system
 In a preparation of Polypeptide Vesicles for drug
Delivery
 In a formulation of Cross linked Polymer micelles
for Cancer Therapeutics

68. EVALUATION OF POLYMER:
Differential scanning calorimetry (DSC)
Gel permeation chromatography (GPL)
Light scattering

69. 1)DIFFERENTIAL SCANNING
CALORIMETRY:
This technique can make
calorimetric measurements of heat capacity and
energies of phase transitions. In case of polymer a
glass transition can be observed as a discontinuity
in the heat capacity.
The degree of crystallinity of
semi –crystalline polymers can be determined
from the heat of melting temperature can easily
be measured and these are often found to depend
on heating rates.

70. 2)GEL PERMEATION
CHOMATOGRAPHY (GPL):
This chromatographic technique
passing a solution of polymer through a coumn
with porous packing . The small molecules are
retained for longer on the column and hence
eluted and detected after the large molecues.
The polymer can be detected as they are
eluted by measuring changes in the refractive
index , infrared absorption, viscosity or light
scattering detectors connected to the output
stream and give a direct measure of the absolute
molecular size.

71. 3)LIGHT SCATTERING :
This method determines the size and the or
mobility of colloides and polymer . It can be
divided into two different techniques
•Static light scattering in which the angular
distribution of scattered intensity is measured to
determine the size of scattering object.
•Dynamic light scattering in which a correlation
function of scattered photons is measured and is
measured and if often used to determine mobility
and to deduce a hydrodynamic size.

72. References :
Targeted and controlled drug delivery by
S.P.VYAS & R.K.KHAR
Robinson , CDDS
N.K.JAIN, CDDS
Encyclopedia of controlled drug delivery
system
www.google.com