This document discusses biodegradable polymeric delivery systems for drug delivery. It describes how biodegradable polymers can be used as carriers for proteins and peptides. Some key biodegradable polymers mentioned include poly(lactide-co-glycolide) and poly(hydroxybutyrate-co-valerate). The document discusses the characteristics of ideal polymers for drug delivery and criteria for polymer selection. It also provides details on controlled release mechanisms and compares delivery system designs.

1. Biodegradable Polymeric Delivery System
PPrreesseenntteedd BByy::
Sunil Kamboj
Roll No: 1211533
DEPARTMENT OF CHEMICAL ENGINEERING
JMIT, Radaur- 135133

2.  A large number of the carriers have been designed for delivery of
proteins and peptides via liposome, niosome, polymeric nanoparticles,
solid lipid nanoparticles etc.
 Polymer based carriers have taken much attention of the scientific
community for safe and effective delivery of proteins.
 Biodegradable polymers is used through slight modifications of their
structures.
 Biodegradable polymers have a great applications in pharmaceutical,
medical and biomedical engineering.
 Biodegradable polymers are not limited to release of drugs, peptides or
proteins but are also extended to medical devices and wound dressing.

3. Polymer?
• Large molecule composed of a number of sub-units
- Natural e.g. alginates,
- synthetic e.g. poly(HMPA)
- Function governed by number and arrangement of constitutional repeat
units e.g. –[A-]n, -[A-B-]n, -[A-A] n-[B-B] m , --A-A-B-A-B-B-A-
• How are they made?
- Processing of natural products – alginates from seaweeds, celluloses
from plants
- Synthesis from chemical feedstocks – poly(olefins), nylons, poly(esters)
• How can they help?
- Protection of therapeutic compound during passage through body, as
encapsulant or carrier.
- Mediator or activator of controlled release

4. CHARACTERISTICS OF IDEAL POLYMER
Should be inert and compatible with the
environment.
Should be non-toxic.
Should be easily administered.
Should be easy and inexpensive to
fabricate.
Should have good mechanical strength.

5. Criteria Followed In Polymer
Selection
It must be soluble and easy to synthesize;
must have a finite molecular wt.
Should provide drug attachment and
release sites for drug polymer linkages.
Should be compatible with biological
environment, i.e. non-toxic and non-antigenic.
Should be biodegradable or be eliminated
from body after its function is over.

6. Biodegradable polymers
- Polymer degrades in vivo to release the drug
- Simple release mechanism, but difficult to obtain fine control
over degradation
- Does not invoke an inflammatory or toxic response.
- It is metabolized in the body after fulfilling its purpose, leaving
no trace
• Common biodegradable polymers
- Poly(lactide-co-glycolide) (PLGA)
- Poly(hydroxybutyrate-co valerate) (Biopol)
• Examples in use
- Resomer (PLGA)
- Vicryl (PLGA)

7. List of Biodegradable Polymers used in Drug Delivery
Natural polymers
Protein-based polymers Collagen, albumin, gelatin
Polysaccharides Agarose, alginate, carrageenan,
hyaluronic acid, dextran,
chitosan,
Cyclodextrins
Synthetic polymers
Polyesters Poly(lactic acid), poly(glycolic
acid),
poly(hydroxy butyrate), poly(ε-
caprolactone),
poly(α-malic acid),
poly(dioxanones)
Polyesters
Polyanhydrides Poly(sebacic acid), poly(adipic
acid),
Continues......

8. Polyamides Poly(imino carbonates), polyamino acids
Phosphorous-based
polymers
Polyphosphates, polyphosphonates,
polyphosphazenes
Others Poly(cyano acrylates), polyurethanes,
polyortho
esters,
polydihydropyrans, polyacetals

9. Polymeric DDS devices
Particulate systems
Nanoparticles
Nanocapsules
Nanospheres
Microparticles
Microspheres
Microcapsules

10. Controlled Release Systems
Controlled release implies controlled release of drugs
from polymer drug delivery systems (DDS)
Type of polymer
Non-degradable / Degradable
Type of Design
Reservoir Matrix
Release mechanisms
Diffusion / polymer degradation / combination

11. Biodegradable Delivery Systems
t = 0 t = n
polymer
drug
Drug is physically incorporated (mixed) into a biocompatible
polymer matrix
Drug is protected by the polymer
Drug migrates from the polymer to the body
Drug is released in a controlled manner
After all drug is released, surgical removal of the polymer is
not necessary
Polymer contains labile bonds

12. Mechanism of Biodegradation
A. Hydrolytic Degradation :
 Breakdown of polymer by water by cleaving
long chain into monomeric acids. This is done
by two ways :
 Bulk eroding polymers
e.g. Polylactic acid (PLA)
Polyglycolic acid (PGA)
 Surface Eroding Polymers
e.g. Polyanhydrides
B. Enzymatic Degradation :
 Exact mechanism is not known but may be
due to lysis of long polymer chain by
attaching to it.

13. Drug delivery from (a) bulk-eroding and (b) surface-eroding biodegradable
systems

14. Biodegradable Delivery Systems
Physical incorporation of a drug in a polymer-based
delivery systems are an improvement to conventional
administration
Drawbacks:
Incorporate low percentages of drug
High potential for drug separation (accidental or
intentional)
Drug is released with a burst

15. Drug Delivery Systems
Plasma drug concentrations
proportional to the dose
Traditional drug dosing requires
repeated administration
Drug is distributed throughout
the body
Maintain therapeutic levels
by a single administration
Drug preservation and
protection
Localize drug delivery
Increase patient comfort and
improve compliance

16. Comparison of Controlled Release System Designs
Polymer Non-degradable Degradable
Design Reservoir Matrix Reservoir Matrix
Release √√√ √√√ √√ √√
Removal √ √
Rupture √ √
Low Mw √ √ √ √
High Mw √ √ √
Duration 5 years 5 years 1-2 years Months
Examples Norplant® Jadelle® CapronorTM Microspheres

17. References

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Shivani Rai, Abhinav Mehta, Shailja Tiwari, Shiva Vyas and Suresh Vyas.
Biodegradable polymer based particulate carrier(s) for the delivery of proteins and
peptides. Anti-Inflammatory and Anti-Allergy Agents in Medicinal Chemistry, 2008, 7:
240-251.
•Gemma Vilar, Judit Tulla-Puche and Fernando Albericio. Polymers and drug delivery
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•Kumaresh Soppimatha, Tejraj Aminabhavia, Anandrao Kulkarnia and Walter
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