Sustained drug delivery systems significantly improve therapeutic efficacy of drugs. Drug-release-retarding polymers are the key performers in sustained release drug delivery system for which various natural, semi-synthetic and synthetic polymeric materials have been investigated. Besides this several polymers are often utilized in the design of novel drug delivery systems such as those that target delivery of the drug to a specific region in the gastrointestinal tract or in response to external stimuli to release the drug.

1. ROLL OF POLYMER IN SUSTAINED
RELEASE DRUG DELIVERY SYSTEM
PRESENTED BY:
PRODIPTA CHAKRABORTY
Department of Pharmaceutics
HIMALAYAN PHARMACY INSTITUTE

2. Introduction:
• Sustained drug delivery systems significantly
improve therapeutic efficacy of drugs. Drug-
release-retarding polymers are the key performers
in sustained release drug delivery system for
which various natural, semi-synthetic and
synthetic polymeric materials have been
investigated. Besides this several polymers are
often utilized in the design of novel drug delivery
systems such as those that target delivery of the
drug to a specific region in the gastrointestinal
tract or in response to external stimuli to release
the drug.

3. Polymer
• Polymers are high molecular weight
compounds or macromolecules composed of
many repeating subunits called
“MONOMERS”, connected by Covalent
bonds or chemical bonds. The reaction
involving combination of two or more
monomer units to form a long chain polymer is
termed as polymerization.

4. Sustained Release Drug Delivery System
• Sustained release drug delivery systems are
designed to achieve a prolonged therapeutic
effect by continuously releasing medication
over an extended period of time after
administration of a single dose.

5. General mechanism of drug release from p
olymer
• There are three primary mechanisms by which active agents can be release
d from a delivery system. These are
1. Diffusion
2. Degradation
3. Swelling

6. Diffusion
• Diffusion occurs when a drug or other active agent passe
s through the polymer that forms the controlled‐release d
evice. Diffusion occurs when the drug passes from the p
olymer matrix into the external environment. As the rele
ase continues its rate normally decreases with this type
of system since the active agent has a progressively long
er distance to travel and therefore requires a longer diffu
sion time to release.

7. Degradation
• Biodegradable polymer degrades within the body as a
result of natural biological processes, eliminating the
need to remove a drug delivery system after release of the active
agent has been completed. Most biodegradable polymers are desi
gned to degrade as a result of hydrolysis of the polymer chains in
to biologically acceptable and progressively smaller compounds.
For some degradable polymers, mostnotably the polyanhydrides
and polyorthoesters, the degradation occurs only at the surface o
f the polymer,resulting in a release rate that is proportional to the
surface area of the drug delivery system.

9. Swelling
• They are initially dry and when placed in the body will absorb water or oth
er body fluids and swell. The swelling increases the aqueous solvent con
tent within the formulation as well as the polymer mesh size, enabling the
drug to diffuse through the swollen network into the external environment.

10. Natural polymer as a sustained release
agent:
• Hibiscus mucilage
The mucilage is extracted from the fresh leaves of Hibiscus
rosasinensis. In an investigation the matrix tablets of Diclofenac
sodium using Hibiscus rosa-sinensis leaves mucilage was design and
study its release retardant activity in prepared sustained release
formulations. Hibiscus rosa-sinensis leaves were evaluated for
physicochemical properties. Different matrix tablets of Diclofenac
sodium Hibiscus rosa-sinensis leaves mucilage were formulated.
The swelling behavior, release rate characteristics and the in-
vitro dissolution study proved that the dried Hibiscus rosa-
sinensis leaves mucilage can be used as a matrix forming
material for preparing sustained release matrix tablets.

11. Aloe mucilage
• The inner part of the leaves of Aloe vera (L.)
Burm.f. (Aloe barbadensis Miller) many
compounds with diverse structures have been
isolated from both the central parenchyma tissue
of Aloe vera leaves and the exudates arising from
the cells adjacent to the vascular bundles. The
dissolution study proved that the dried Aloe
barbadensis miller mucilage and Povidone
combination can be used as a matrix forming
material for making Sustained release matrix.

12. Guar gum
• Guar gum comes from the endosperm of the seed
of the legume plant Cyamopsis tetragonolobus. In
an approach Sustained release tablets of
furosemide were fabricated using pectiA better
controlled drug release (80.74%) was obtained
with the matrix tablet (G4) made-up of the guar
gum than with the pectin and xanthan gum. It is
cleared through the dissolution profile of
furosemide from matrix tablets prepared using
different natural polymers were retarded approx
15 hrs.n, guar gum and xanthan gum.

13. Synthetic polymer as sustained release
agent
• Rosin
Rosin a film-forming biopolymer and its
derivatives have been extensively evaluated
pharmaceutically as film coating and
microencapsulating materials to achieve
sustained release.

14. Cellulose Ethers
• Cellulose ethers are formed by the alkylation
of cellulose. These polymers may be used as a
matrix for the controlled release of therapeutic
agents.
• Ethyl cellulose is used as a matrix to modify
the drug release. So its act as a sustained
release agent.

15. Polyesters
• Homopolymers and copolymers of lactic acid,
glycolic acid and E-hydroxycaproic acid jointly
constitute the aliphatic polyesters. These
polymers undergo hydrolytic degradation.
• Different degradation rates may be obtained by
altering the copolymer composition, molecular
weight, crystallinity and stereochemistry of the
monomer. Polyesters are widely used to formulate
controlled release drug delivery system.

16. Conclusion
• Polymers that are used in pharmaceutical coating
are primarily based on cellulosic and acrylic
polymers, as they both have good film-forming
properties that enable them in the production of
tough protective coatings. Drug release rate is
influenced by factors such as rate of diffusion
across the membrane, tablet coating so that
neither dissolution nor degradation of the polymer
should occur during its active lifetime. Polymers
are playing a significant role in sustained drug
delivery system.

17. Reference
1. Krushnakumar J Gandhi, Subhash V Deshmane, Kailash R Biyani, A
Review on Polymers in Pharmaceutical Drug Delivery
System,International Journal of Pharmaceutical Sciences Rev-
iew and Research, 2012, page no 61-63
2. David Jones, Pharmaceutical Applications of Polymers for Drug
Delivery, Rapra Review Reports, 2014, page no 1-17
3. Ashish Chauhan, Use of Polymers in Sustained Drug Release System,
Open Access Scientific Reports, 2012, page no 1-6