This document discusses polymers and their role in drug delivery systems. It defines polymers as large molecules composed of repeating structural units or monomers connected by covalent bonds. Polymers are used in drug delivery for their controlled release, masking, protective and stabilizing properties. The document outlines the history of polymer drug conjugates, characteristics of ideal polymers, criteria for polymer selection, advantages like increased drug stability and solubility, and disadvantages like initial burst release. Finally, it describes the roles of polymers in controlled release systems, modified release formulations, and gastroretentive dosage forms to prolong drug release.
2. POINTSTO BE COVERED:
• Introduction
• Why we use polymer?
• History
• Characteristics of an ideal polymer
• Criteria followed in polymer selection
• Advantages
• Disadvantages
• Role of polymer in drug delivery system
3. INTRODUCTION
Polymer-: Poly + Mer,
i.e. Poly = Many. Mer = Parts
Definition-: The compound having high molecular masses and formed by monomers are termed as
polymer.
Or
Polymer is a substance composed of molecules with large molecular mass composed of repeating structural
unit or monomer, connected by covalent chemical bond.
The word polymer is derived from the greek word Polu – “many” merous – “Part”
Monomer-: A monomer is a small molecule that combines with other molecules of the same or different
types to form a polymer.
. Polymer are just like – e.g. Plastic, DNA, Insulin,Protein
4. WHYWE USE POLYMER ?
• Polymers play vital role in advanced drug delivery system with it’s
controled release masking,protective, stabilizing properties.
• Their application in drug delivery system has been identified because of
their unique properties.
5. HISTORY
• The first polymer drug conjugate appeared around 1995.Being mescaline – N –
vinylpyrrolidone conjugate one of the first.
• In 1994,The first synthetic polymer drug conjugate designed to treat cancer was clinically
tested
It consisted on an HPMA [N-C-2-hydroxypropyl methacrylamide ) copolymer conjugate
of doxorubicin
• In recent -2000,Two polymer protein conjugates,[ PEG- interferon alpha ] (an antiviral
drug intended to treat chronic hepatitis C & hepatitis B) and [PEG – GCSF] (PEG
granulocytes colony stimulating Factor ) were place in market and five years later the first
therapeutic nanoparticle [ Albumin – entrapped paclitaxel ) was approved as a treatment
for metastatic breast cancer.
6. CHARACTERISTICS OF AN IDEAL POLYMER
IT SHOULD BE...
1. Versatile and possess a wide range of mechanical, physical, chemical properties
2. Non toxic and have good mechanical strength and should be easily
administered.
3. Inexpensive and easy to fabricate.
4. Inert and compatible with environment.
5. Have Low density.
6. Low coefficient of friction
7. Have good resistance of corrosion.
8. Good mould ability.
9. Temperature resistance.
10. Produced in transparent or in different colours..
7. CRITERIA FOLLOWED IN POLYMER
SELECTION:
1. The polymer should be soluble and easy to synthesize.
2. It should have finite molecular weight
3. Compatible with biological environment
4. Should be biodegradable
5. It should provide good drug polymer linkage
8. ADVANTAGES OF POLYMER
• Inert carrier enhances the pharmacokinetics and pharmacodynamic properties of biopharmaceuticals.
• Increases the half life of drug.
• Decreases immunogenicity.
• Boost stability of biopharmaceuticals.
• Increases solubility of low molecular drugs.
• Localised delivery of drug.
• Sustain delivery of drug.
• Decreases the dosing frequency.
• Improve patient compliance.
• Biodegradable and biocompatible.
• Have potential for targeted drug delivery system.
9. DISADVANTAGE OF POLYMER
• Exhibit dose dumping effect.
• High initial drug release after administration.
• Low mechanical properties.
10. ROLE OF POLYMER IN DRUG DELIVERY
SYSTEM
1. In Controled Drug delivery system
• Reservoir system
• Matrix system
• Swelling controlled release system
• Biodegradable system
11. 2. Immediate Drug doses form tablet and capsule:
• polymer including polyvinyl pyrrolidone and hydroxyl propyl methylcellulose (HPMC) are
found to be a good binder which increases the Flow and Compaction properties of tablet
formulation prior to tableting.
• Capsule – recently advance HPMC has been accepted as alternative material are used to
bulk out capsule fills.
12. 3.Modified drug release:
• To achieve gastro retention mucoadhesive and low density polymer have been
evaluated
• It extended the gastric residence time by bbonding to the mucus lining of
stomach and floating on top of gastric contents.
13. 4. Extended release dosage forms:
• Extended and sustained release dosage form prolonged the time that
systemic drug levels are within therapeutic range & thus reduce the
number of dosage the patient must taken take to maintain in the
therapeutic effect
• Eg. Ammonium ethacrylate, cellusoe acetate, polyvinyl
derivatives .
14. 5. Gastro rententive dosage form
• Gastro rententive dosage forms offers an alternative strategy for an
achieving extended release profile, in which the formulation will
remains in stomach for prolonged period releasing the drug insitu
which will dissolve in liquid content.