Biodegradable Polymers

Biodegradable Polymeric Delivery System
Drug delivery system

1. Biodegradable Polymeric Delivery System
Presented By:Presented By:
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
•Examples in use
-Resomer (PLGA)
-Vicryl (PLGA)
•Common biodegradable polymers
-Poly(lactide-co-glycolide) (PLGA)
-Poly(hydroxybutyrate-co valerate) (Biopol)

7. List of Biodegradable Polymers used in Drug Delivery
Natural polymers
Protein-based polymersCollagen, 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 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
Controlled Release Systems

11. Biodegradable Delivery Systems
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
t = 0 t = n
polymer
drug

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. 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
Biodegradable Delivery Systems

15. 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
Drug Delivery Systems

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
®
Capronor
TMMicrospheres

17. References

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Biodegradable polymer based particulate carrier(s) for the delivery of proteins and
peptides. Anti-Inflammatory and Anti-Allergy Agents in Medicinal Chemistry, 2008, 7:
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•Gemma Vilar, Judit Tulla-Puche and Fernando Albericio. Polymers and drug delivery
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