Polymers are becoming increasingly important in the field of drug delivery. The pharmaceutical applications of polymers range from their use as binders in tablets to viscosity and flow controlling agents in liquids, suspensions and emulsions. 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. As a consequence, increasing attention has been focused on methods of giving drugs continually for a prolonged time periods and in a controlled fashion. This technology now spans many fields and includes pharmaceutical, food and agricultural applications, pesticides, cosmetics, and household products.

1. M.Pharm 2nd Semester Seminar
Subject : Advanced Physical Pharmacy
Topic : Application Of Polymer In Controlled Release Formulation
By:
Anindya Jana
M.Pharm 1st Year (Pharmaceutics)
Regd. No. : 1661611006

2. Polymer
The word “polymer” means “many
parts.” A polymer is a large
molecule made up of many small
repeating units.
Polymers are considered to be a
subset of macromolecules.
Macromolecule refers to any large
molecule.
A monomer is a small molecule
that combines with other
molecules of the same or different
types to form a polymer.

3. Controlled Drug Delivery System (CDDS)
Controlled release is a term referring
to the delivery of compounds in
response to time.
Controlled release systems have been
developed to protect drug from
physiological degradation or
elimination, to improve patient
compliance, and to enhance quality
control in manufacturing of drug
products.

4. Classification Of Polymers
Natural Polymer
1. Protien-based polymer: Collagen, Albumin, Gelatin
2. Polysaccharides: Alginate, Cyclodextrin, Chitosan, Dextran, Agarose, Hyaluronic acid, Starch,
Cellulose
Synthetic Polymers
Biodegradable Polymer
a) Polyester: Poly lactic acid, Poly glycolic acid Poly hydroxyl butyrate, Polyester,
Polycaprolactone Poly lactide-co-glycolide (PLGA), Poly diaxonone
b) Polyanhydride: Poly adepic acid, Poly sebacic acid Poly terpthalic acid
c) Polyamides: Poly amino acid, Poly imino carbonate

5. d) Phosphorous based polymer: Polyphosphates, Poly phosphonates, Poly Phosphazenes
e) Others: Poly cyanoacrylates, Poly urethanes, Poly ortho ester, Polyacetals etc.
Non-Biodegradable polymers
a) Cellulose derivative: Carboxy methyl cellulose, Ethyl cellulose Cellulose acetate hydroxyl
propyl methyl cellulose
b) Silicons: Polydimethyl siloxane, Colloidal silica, Polymethacrylate, Polymethyl methacrylate
c) Others: Poly vinyl pyrolidine, Ethyl vinyl acetate, Poloxamine etc.

6. Release Of Therapeutic Agents From Controlled Release
System
1. Matrix System
In matrix designed drug delivery systems, the drug is homogeneously dispersed, either at the
molecular scale or as solid particles, within a polymeric medium.
Example
(a) Mixing of a polymer with the drug particles followed by direct compression into tablets.
(b) Dissolving the drug and polymer in an appropriate solvent followed by solvent removal.
(c) By hydrogel swelling within a drug solution.
(d) Curing a polymer in the presence of dissolved / dispersed drug.
2. Reservoir Systems
In these systems the drug-containing core is
separated from the biological fluids by a water
insoluble polymeric coat or layer, depending on the
geometry of the drug delivery system.

7. Applications of Polymers for Controlled Drug
Delivery
1. The Ocusert System
The delivery of therapeutic agents to the eye
for the treatment of disorders of the eye, (e.g.,
glaucoma), using conventional drug delivery
systems, e.g., drops, ointments, is an inefficient
process.
The efficiency of ocular drug delivery is
improved through the use of polymeric
implants that are implanted under the lower
cul-de-sac of the eye. In this system pilocarpine
is dispersed within an alginic acid matrix which
is sandwiched between two layers each
composed of poly(ethy1ene-co-vinyl acetate).
It is designed to release either 20 µg/h or 40
µg/h of a therapeutic agent for a seven day
period following implantation.

8. 2. Transdermal Patches
Transdermal drug delivery 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
thereby preventing drug loss, 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).

9. Literature Articles
1. Choi W. Y. et al. has developed a matrix-type, controlled-release tablet formulation of pelubiprofen
(PLB), a recently developed non-steroidal anti-inflammatory drug. He used polymeric excipients including
hypromellose, hydroxypropylcellulose, Eudragit® RS PO, and Kollidon®SR.

10. A formulation containing 12.4% w/w Kollidon SR (K2 tablet) was found the most
promising and stable for 6 months in an accelerated stability test. PLB release
from K2 tablet was limited at pH 1.2, but gradually increased at pH 6.8 with a
surface-erosion.

11. 2. Andersson H et. al. has done the investigation the effect of the molecular
weight of HPC on the microstructure and mass transport in phase-separated
freestanding Hydroxypropyl cellulose (HPC) / ethyl cellulose (EC) films with
30% w/w HPC.
• Four different HPC grades were used, with weight averaged molecular
weights (Mw) of 30.0 (SSL), 55.0 (SL), 83.5 (L) and 365 (M) kg/mol.
• Size Exclusion Chromatography with multi-angle light scattering and
refractive index detection (SEC-MALS/RI) has used to determine z-average
molar mass (Mz), weight average molar mass (Mw) and number average
molar mass (Mn) .
• The permeability has considered an effective diffusion coefficient in the film.
The water permeabilities of the films were determined from radioactive
tracer diffusion across the films in the diffusion cell, assuming direct
proportionality between the radioactivity and diffused mass.

13. The film with the lowest Mw HPC (SSL) had unconnected oval-shaped HPC-rich
domains, leaked almost no HPC and had the lowest water permeability. The
remaining higher Mw films had connected complex-shaped pores, which
resulted in higher permeabilities. The highest Mw film (M) had the smallest
pores and very slow HPC leakage, which led to a slow increase in permeability.
Films with grade L and SL released most of their HPC, yet the permeability of
the L film was three times higher due to greater pore connectivity. It was
concluded that the phase-separated microstructure, the level of pore
percolation and the leakage rate of HPC will be affected by the choice of HPC
Mw grade used in the film and this will in turn have strong impact on the film
permeability.

14. References :
1. D Jones; Pharmaceutical Application For Drug Delivery; Rapra Review Reports; Volume 15;
Number 6; 2004. Page 18 -25
2. Chauhan P S N et al.; Pharmaceutical Polymer; Encyclopedia of Biomedical Polymers and
Polymeric Biomaterials; 2016; Page 5931
3. Gavasane A et al.; Synthetic Biodegradable Polymers Used in Controlled Drug Delivery
System; Clinical Pharmacology & Biopharmaceutics; 2014; Page 1-2
4. Bhoumik D et al.; Controlled Release Drug Delivery Systems; The Pharma Innovation; Volume
1; Number 10; 2012; Page 30-31
5. Choi W Y at el.; Formulation of controlled-release pelubiprofen tablet using Kollidon1 SR;
International Journal of Pharmaceutics; Elsevier; 2016; P 564-875
6. Andersson H at el.; The influence of the molecular weight of the water-soluble polymer on
phase-separated films for controlled release; International Journal of Pharmaceutics; Elsevier;
2016; Page 223-235

15. Thank You