ROLE OF POLYMERS IN CONTROLLED RELEASE DRUG DELIVERY SYSTEM

2. CONTENTS
 INTRODUCTION (POLYMERS & CRDDS)
 MEDICAL RATIONALE BEHIND CRDDS
 CLASSIFICATION OF POLYMERS
 ADVANTAGES
 RELEASE OF THERAPEUTIC AGENTS FROM CONTROLLED RELEASE
SYSTEM
 APPLICATION OF POLYMER IN CRDDS
 REFERENCES
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3.  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.
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5.  The word polymer has been
derived from Greek words, poly
means ‘many’ and mers means
‘parts of unit of high molecular
mass’
 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
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6. 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
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8. Controlled medication delivery has become one of the
most demanding and rapidly growing scientific fields in the
last four decades.
Polymers are the most promising option for controlled drug
administration because of their attractive, flexible features
and ease of production at industrial scale, and potential for
further modification.
Polymer therapeutics include linear or branched polymer
chains that act as a bioactive molecule, such as polymeric
drugs, or as an inert carrier for a drug.
Polymers play an important part in the advancement of
drug delivery technology by offering long repetitive dose
and coordinated release of medicines.
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9. Polymers were mainly used because of their physical properties, for
example:
Poly (urethanes) for elasticity.
Poly (siloxanes) or silicones for insulating ability.
Poly (methyl methacrylate) for physical strength & transparency.
Poly (vinyl alcohol) for hydrophilicity and strength.
Poly (ethylene) for toughness and lack of swelling.
Poly (vinyl pyrrolidone) for suspension capabilities.
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10.  Drug Release from Polymer by Diffusion
Rate limiting step is diffusion of drug through inert water insoluble
membrane barrier.There are of two types:
1. Reservoir 2. Matrix
1. Reservoir Diffusion System:
In membrane-controlled reservoir devices, the drug is
contained in a core, which is surrounded by a polymer
membrane, and it is released by diffusion through this
rate controlling membrane.
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11. Reservoir Diffusion System:
For example,
Poly (N-vinyl pyrrolidone),
Poly (ethylene-co-vinyl
acetate).
Drug delivery from typical
reservoir devices:
(i)Implantable or oral
systems, and
(ii)Transdermal systems.
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13. The delivery of therapeutic
agents to the eye for the treatment
of disorders of the eye, (e.g.,
glaucoma).
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).
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14. 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).
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15. Semi-permeable membrane is made from biocompatible polymers.
E.g. cellulose acetate
Example of such type of system include, Acutrim tablet which contains
Phenylpropanolamine as a drug.
In this device, an osmotic agent is contained within a rigid housing and is separated
from an active agent compartment-b, a movable partition.
One wall of the rigid housing is a semi permeable membrane so that when the pump
is exposed to an aqueous environment, water will be driven osmotically across the
membrane, the increased volume within the osmotic compartment will force the
active agent out of the device through the delivery orifice.
Major application is for gastro intestinal drug deliveries because delivery rate is pH
independent.
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16.  D Jones; Pharmaceutical Application For Drug Delivery; Rapra
Review Reports; Volume 15; Number 6; 2004. Page 18 -25
 Chauhan P S N et al.; Pharmaceutical Polymer; Encyclopedia
of Biomedical Polymers and Polymeric Biomaterials; 2016; Page
5931
 Gavasane A et al.; Synthetic Biodegradable Polymers Used in
Controlled Drug Delivery System; Clinical Pharmacology &
Biopharmaceutics; 2014; Page 1-2
 Bhoumik D et al.; Controlled Release Drug Delivery Systems;
The Pharma Innovation; Volume 1; Number 10; 2012; Page 30-
31
 Tirpathi Dk and Alexander Amit; a text book of “NOVEL DRUG
DELIVERY SYSTEM” third edition 2019,published by BSP book
Pvt. Ltd, page no.1-63
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