Polymer is a heart of controlled drug delivery system. Application of polymers are increasing in pharmaceuticals these days .

1. Presented by:
Pranali .M Palandurkar
University department of
pharmaceutical Sciences
R.T.M.N.U Nagpur

2. Contents
Introduction
Classification
Properties
Advantages
Applications

3. • “Polymer are long chain organic molecules assembled form many smaller
molecules called as monomer connected by covalent bonds or chemical bonds”
• Polymers are macromolecules having very large chains contain a variety of
functional groups, can be blended with other low and high molecular weight
material
• A polymer with two different monomers is known as a copolymer or
homopolymer
• Their use for biomedical and pharmaceutical applications has gained an
enormous impact during the past decades.
• The pharmaceutical applications of polymers range from their use as binders in
tablets to viscosity and flow controlling agents in liquids, suspensions, and
emulsion. 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.

4. • The reaction involving combination of
two or more monomer units to form a
long chain polymer is termed as
polymerization
• By changing the molecular weight, the
physical and mechanical properties of
the polymer can be tailor-made. This
can be achieved by changing the
structure of the monomer building
blocks or by blending them with other
polymers.

5. Natural polymer
• Natural polymers are the
substances which are
obtained by natural
sources like plant and
animal sources.
• The specific application of
plant derived polymer in
pharmaceutical
formulations include their
use in the manufacture of
solid monolithic matrix
systems, implants, etc
• Examples-Proteins-
collagen, keratin, albumin.
Synthetic polymer
• Synthetic polymers are
industrially produced
chemical substances
consisting of a number of
molecules linked together
with covalent bond.
• A wide variety of synthetic
polymers are available with
variation in main chain as
well as side chain.
• Exanple- polyester,
polyanhydrides, polyamides,
polyglycolic acid
A) Based on origin
Semi Synthetic
• Synthetic polymers are
polymers obtained by
making modification in
natural polymers artificially
in a lab.
• These polymers formed by
chemical reaction and are of
commercial importance
• Example-cellulose derivative
(rayon)

6. B) Based on Bio-stability
Bio-
degradable
Polymers
• A Bio-degradable polymer is a polymer in
which the degradation results from the action
of naturally occurring microorganisms such
as bacteria, fungi.
• Examples-Albumin, Collagen, Gelatin, Starch
etc.
Non-
biodegradable
polymer
• The polymers which are not decomposed by
the action of microorganisms and are referred
to as non-biodegradable polymers.
• Example -polyethene, polystyrene

7. C) Based on structure
Linear polymer
• The smallest
repeating
unit arrange
in straight
line path
• Example –
polyvinyl
chloride
Branched
chain polymer
• Contain
linear chain
having some
branches
• Example-
Low density
polymer
Cross linked
chain polymer
• Formed from
bi-functional
and
trifunctional
monomer and
contain strong
covalent
bonds
• Example-
Bakelite
,melamine

8. a) Elastomers: Elastomers are rubber-like solid polymers, that are elastic in nature i.e
stretched by applying a little force. Example -Neoprene rubber, buna-s and buna-n
b) Thermoplastic polymers :Polymers which contain intermolecular forces higher
than Elastomers but less than Fibers. They are usually linear chain polymers and
can be remolded again. Examples: Polythene, Polyvinyl Chlorides, etc.
c) Thermosetting plastics : Polymer which are having highly branched chain
molecules with extensive cross linking and if heated becomes infusible and cannot
be reused. Example: melamine, Bakelite etc.
d) Fibres:Polymers which are a thread like in nature, and can easily be woven. They
have strong inter-molecules forces between the chains giving them less elasticity
and high tensile strength. The intermolecular forces may be hydrogen bonds or
dipole-dipole interaction. Fibres have sharp and high melting points. Example:
Nylon-66.
D)Based on Molecular Force

9. • These type of polymers are formed by the repeated addition of monomer
molecules with double or triple bonds.
• Addition polymers always have their empirical formulas same as their
monomers. Example: ethene n(CH2=CH2) to polyethene -(CH2-CH2)n-
Addition polymers:
• These polymers are formed by the combination of monomers, with the elimination
of small molecules like water, alcohol etc..
• The monomers in these types of condensation reactions are bi-functional or tri-
functional in nature.
• A common example is the polymerization of Hexamethylenediamine and adipic
acid. to give Nylon – 66, where molecules of water are eliminated in the process
Condensation polymers:
E)Based on Mode of Polymerization

10. A) Crystalline and amorphous polymers:
• Amorphous or glassy polymers do not generally display a sharp melting
point; instead, they soften over a wide temperature range.
• Polymer strength and stiffness increases with crystallinity as a result of
increased intermolecular interactions.
• From a pharmaceutical prospective, good barrier properties are needed
when polymers are used as a packaging material or as a coating.
Crystallinity increases the barrier properties of the polymer.
• On the other hand, a less crystalline, or an amorphous polymer is preferred
when the release of a drug or an active material is intended.

11. B) Thermal transitions
• Thermal transitions in polymers can occur in different orders.
• That is, the volume of a polymer can change with temperature as a first-or
second-order transition. When a crystal melts , the polymer volume
increases significantly as the solid turns to a liquid. The melting temperature
(Tm) represents a first-order thermal transition in polymers. On the other
hand, the volume of an amorphous polymer gradually changes over a wide
temperature range or so-called glass transition temperature. This behaviour
represents a second-order thermal transition in polymers .

12. C) Plasticized polymer
• A plasticizer is added to a polymer formulation to enhance its flexibility and to help its
processing. It facilitates relative movement of polymer chains against each other. This
results in a reduction in the glass transition temperature of the mixture.
• Since plasticizers increase molecular motion, drug molecules can diffuse through the
plasticized polymer matrix at a higher rate depending on the plasticizer concentration
D) Molecular weight
• There are different ways that molecular weights of a polymer can be expressed:
• by the number of the chains,
• by the weight of the chains (the chain size),
• or by viscosity.
• However, the two most common ways are number (Mn) and weight (Mw) average
calculations.
• Based on that polymers can be termed as polydispered and monodispersed.

13. E) Mechanical properties
• Depending on their structure, molecular weight, and intermolecular forces,
polymers resist differently when they are stressed.
• They can resist against stretching,compression, bending and dynamic loading.
With increasing molecular weight the level of intermolecular forces, polymers
display superior properties under an applied stress
F) Viscoelastic Properties
• Materials that exhibit both viscous and elastic characteristics when deformed
under stress are known to be viscoelastic.
• Polymers are neither a pure elastic nor a pure fluid material. They have the
ability to store energy (display elastic behaviour ) and to dissipate it (display
viscous behaviour ). For this reason, most polymers are viscoelastic materials.

14. • The polymer enhances the pharmacodynamic and pharmacokinetic properties of
biopharmaceuticals though several sources, such as, increases the plasma ½ life,
decreases the immunogenicity, boost stability of biopharmaceuticals,
• Polymer can also improves solubility of low molecular weight drugs, and has
potential for targeted drug delivery
• Sustained delivery of drug can be achieved by polymers hence decrease in dosing
frequency.
• Polymer can be use for taste masking of bitter drug which increases the patient
compliance .
• Localised delivery of drug-The product can be implanted directly at the site where
drug action is needed
• Due to biodegradable polymers their degradability reduces the need for subsequent
surgical removal, saving time and money
• The polymer can protect the drug from the physiological environment and hence
improve its stability in vivo

15. Controlled drug delivery occurs when a polymer ,whether natural or
synthetic, is judiciously combined with a drug or other active agents such
away that the active agent is released from the material in a predesigned
manner .
1.Extended release dosage forms: Extended and sustained release dosage forms
prolong the time that’ systemic drug levels are within the therapeutic range and
thus reduce the number of doses the patient must take to maintain a therapeutic
effect there by increasing compliance. The most commonly used water insoluble
polymers for extended release applications are the ammonium ethacrylate
copolymers cellulose derivatives ethyl cellulose and cellulose acetate, and
polyvinyl derivative, polyvinyl acetate

16. 2.Gastro retentive Dosage forms: To achieve gastro retention mucoadhesive
and low density, polymers have been evaluated, with little success so far their
ability to extend gastric residence time by bonding to the mucus lining of the
stomach and floating on top of the gastric contents respectively.

17. 3.Ocular drug delivery system –It allows prolonged contact with corneal
surface of eye .
Example –Pillocarpine in the treatment of glaucoma –In this mucoadhesive
polymers (Polyacrylic acid or copolymer of acetate vinyl &ethyl) are used as
barrier to control the drug release.
The efficiency of ocular drug delivery is improved through the use of
polymeric implants i.e Occusert that are implanted under the cul-de-sac of the
eye.

18. 4.Trandermal drug delivery –It involves the diffusion of the drug through the
skin and ultimately absorption into the systemic circulation.
The drug delivery system is composed of several layers, namely a metallic
backing layer ,which is impermeable to drug diffusion ,the drug containing
reservoir, a rate controlling membrane and an adhesive layer.
In the matrix drug is dissolved or dispersed with solid polymer(acrylate co –
polymer)

19. 5.Polymers in nanoparticles Nanoparticles have size range of 10-1000nm. In
nanoparticle drug delivary system drug is attached, entrapped and dissolve to
polymeric matrix. Example of synthetic biodegradable polymers are poly
lactide, poly(lactide-co-glyolide), poly-ɛ-caprolactone and polyanhydrides.