Biodegradable Polymeric Delivery System

Presented By:Presented By:

Sunil Kamboj

Roll No: 1211533

DEPARTMENT OF CHEMICAL ENGINEERING

JMIT, Radaur- 135133

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.

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

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.

Criteria Followed In Polymer SelectionIt 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.

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)

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......

Polyamides Poly(imino carbonates), polyamino acids

Phosphorous-based polymers

Polyphosphates, polyphosphonates, polyphosphazenes

Others Poly(cyano acrylates), polyurethanes, polyorthoesters,polydihydropyrans, polyacetals

Polymeric DDS devicesParticulate systems

NanoparticlesNanocapsulesNanospheres

Microparticles MicrospheresMicrocapsules

Controlled release implies controlled release of drugs from polymer drug delivery systems (DDS)

Type of polymerNon-degradable / Degradable

Type of Design

Reservoir Matrix

Release mechanismsDiffusion / polymer degradation / combination

Controlled Release Systems

Biodegradable Delivery Systems

Drug is physically incorporated (mixed) into a biocompatible polymer matrixDrug is protected by the polymer

Drug migrates from the polymer to the bodyDrug is released in a controlled manner

After all drug is released, surgical removal of the polymer is not necessaryPolymer contains labile bonds

t = 0 t = n

polymer

drug

Mechanism of BiodegradationA. Hydrolytic Degradation : Breakdown of polymer by water by cleaving

long chain into monomeric acids. This is done by two ways :

Bulk eroding polymerse.g. Polylactic acid (PLA)

Polyglycolic acid (PGA) Surface Eroding Polymers

e.g. PolyanhydridesB. Enzymatic Degradation : Exact mechanism is not known but may be

due to lysis of long polymer chain by attaching to it.

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

Physical incorporation of a drug in a polymer-based delivery systems are an improvement to conventional administration

Drawbacks:Incorporate low percentages of drugHigh potential for drug separation (accidental or

intentional)Drug is released with a burst

Biodegradable 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 deliveryIncrease patient comfort and

improve compliance

Drug Delivery Systems

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

References

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