Detailed introduction to biodegradable polymers and introduction to chitosan.

1. Biodegradable polymers in
drug delivery system
Presented By
Guided By
MS. KRUTIKA H. PARDESHI MR.A.D.SAVKARE
M.Pharm(Pharmaceutics) (Assistant professor)
Sem -I, Roll no. 37
NDMVP SAMAJ’S COLLEGE OF PHARMACY, NASHIK
M.Pharm Semester I -seminar

2. CONTENT
• Introduction to Polymers
• Classification of polymers
• Biodegradable polymers
- Definition
- Classification
- Examples
- Mechanism of action
- Need of biodegradable polymer
- Advantages and disadvantages
- Applications
• Chitosan as a polymer
- Introduction
- Chemistry
- Applications
• conclusion
• References
2

3. • Polymers
• Polymer means -“many parts”
• Definition –
“Polymer is a substance of high molar mass that is composed
of repeating structural units”
Example – Ethyl cellulose
Carboxy-methyl cellulose
Poly (vinyl alcohol)
Polyethylene etc.
3
Ethylene Polyethylene

4. • Classification
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5. 5
• Natural polymers obtained from natural plants,
animal, microbial sources.eg. Cotton, Silk, Wool.
• Semi synthetic and synthetic obtained from
synthetic route of polymerization.eg. PE,PVC.
1. Based on
origin of
source
• Linear
• Branched
• cross-linked
2. Based on
structure
3. Based on
molecular
forces
4. Based on
mode of
polymerization

6. • Biodegradablepolymers
6
• Polymers that are degradable in vivo, either enzymatically or non
enzymatically, to produce biocompatible or nontoxic by-products.
• By products are metabolized and removed from the body via
normal metabolic pathways.
• Example-
1.poly vinyl alcohol
2. poly lactic acid
3. poly glycolic acid
4. pectin
5. collagen
6. starch etc.

7. • Classification
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8. 1. Agroresources
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• POLYSACCHARIDE :-
• Most abundant complex
carbohydrate.
• Structural element- glycosidic
bond
• Example- starch, chitin,
chitosan , pectin, etc.
• PROTEIN :-
• Renewable resources produce
by animal, plant, bacteria.
• Example- soya protein, casein,
collagen, chymotrypsin.

9. 2. From micro-organisms
POLYHYDROXY ALKONATE (PHA) POLYHYDROXY BUTYRATE (PHB)
-Some organisms accumulate PHA
from 30% to 80% of their cellular dry
weight.
-The general formula of the monomer
unit is -[O-CH(R)-CH2-CO]-
-Mechanical properties of PHA : Rigid
brittle plastics to flexible plastics.
-PHAs are wholly biodegradable.
-Biodegradation occurs via linkage break
by esterase enzyme.
-The R alkyl substituent group is
methyl.
-PHB is highly crystalline. Its melting
temperature is 180 °C.
-The pure homopolymer is a brittle
material.
-PHB is susceptible to thermal
degradation at temperatures in the
region of the melting point
-PHB is degraded by numerous
microorganisms (bacteria, fungi and
algae)
-The hydrolytic degradation yields to
the formation of 3-hydroxy butyric
acid, which is normal constituent of
blood.
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10. 3. From biotechnologicalsynthesis
PGA(POLYGLYCOLIDE)
• PGA is the simplest linear aliphatic polyester. It is prepared by ring
opening polymerization of a cyclic lactone, glycolide.
• It is highly crystalline, and thus is not soluble in most organic
solvents. It has a high melting point (220-225 °C)
• PGA has excellent mechanical properties.
• Its biomedical applications are limited by its low solubility and its
high rate of degradation yielding acidic products.
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11. PLA(POLYLACTIDE)
• PLA , a cyclic dimer of lactic acid, is usually obtained from
polycondensation of D- or L-lactic acid or from ring opening
polymerization of lactide.
• Two optical forms exist: D-lactide and L-lactide(natural), and
synthetic blend is DL-lactide.
• PLA is a hydrophobic polymer due to the presence of –CH3 side
groups
• PLA has disadvantages of brittleness and poor thermal stability.
• PLA can be plasticized with citrate ester or low molecular
polyethylene glycol to improve the chain mobility and to favour its
crystallization.
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12. • Synthetic route :-
i) ring opening polymerization :- high molecular weight PLAs with
better mechanical properties obtained.
ii) solid state polymerization
iii)solution polymerization or chain extension.
• The biodegradability of PLA can enhanced by graft copolymerization
of L-lactide onto chitosan using ring opening polymerization and tin
as a catalyst.
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13. 4. Conventionalsynthesisfrom oil
products
POLYCAPROLACTONE(PCL)
• A semi-crystalline linear polymer obtained from ring-opening
polymerization of ε-caprolactone in presence of tin octoate catalyst.
• PCL is soluble in a wide range of solvents.
• its melting point is 60 – 65 °C. PCL is a semi-rigid material at room
temperature.
• Enzymes and fungi easily biodegrade PCL. To improve the
degradation rate, several copolymers with lactide or glycolide have
been prepared .
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14. POLY-ESTER AMIDES
• Copolymers with amide and ester groups are found to be readily
degraded.
• The rate of degradation increases with increasing ester content.
• Aliphatic poly(ester-amide)s have been synthesized from 1.6 -
hexanediol, glycine and di-acids with a various number of methylene
groups varying from 2 to 8.
• All these polymers are highly crystalline.
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15. • Mechanismofdrugreleasefrombiodegradablepolymer
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COMBINATIONHYDROLYSIS
BULK EROSION SURFACE EROSION
ENZYMATIC

16. • BIOEROSION
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1) Bulk erosion
- Degradation takes place throughout
the whole of the sample.
- Ingress of water is faster than the
rate of degradation
E.g. : Polylactic acid (PLA)
Polyglycolic acid (PGA)
2) Surface erosion
-Sample is eroded from the surface.
-Mass loss is faster than the ingress of water
into the bulk
E.g.: Polyanhydrides
polyorthoester

17. • RELEASEOFDRUGFROMSRTABLET USING
HYDROPHILLICMETRIXFORMINGPOLYMER
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18. • NEED OFBIODEGRADABLEPOLYMER
1) Achieving controlled drug delivery.
2) No need for a second surgery for removal of Polymers.
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19. • ADVANTAGES& DISADVANTAGES
• ADVANTAGES • DISADVANTAGES
• Localized delivery of drug
• Sustained delivery of drug
• Stabilization of drug
• Decrease in dosing frequency
• Reduce side effects
• Improved patient compliance
• Presence of substances that
may be issued in the body
[monomers (toxic), catalysts,
additives] after Degradation
• A “burst effect” or high initial
drug release soon after
administration is typical of
most system.
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20. • APPLICATIONS
• Polymer system for gene therapy.
• Biodegradable polymer for ocular, tissue engineering, vascular,
orthopedic, skin adhesive & surgical glues.
• Bio degradable drug system for therapeutic agents such as anti
tumor, antipsychotic agent, anti-inflammatory agent.
• Polymeric materials are used in and on soil to improve aeration, and
promote plant growth and health.
• Many biomaterials, especially heart valve replacements and blood
vessels, are made of polymers like Dacron, Teflon and polyurethane. 20

21. POLYMER APPLICATION
• Collagen In wound repairing
• Chitosan Gelling agent
• Dextran Plasma volume expander
• Lectins As a mucoadhesive
• Cyclodextrins,
guar gum, pectin, insulin
Delivery of drug to colon
• Rosin As an adhesive in TDDS 21

22. CHITOSAN AS A POLYMER
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23. • INTRODUCTION
• Chitosan is a natural cationic biopolymer consequent
commencing the hydrolysis of chitin.
• Obtained from ecologically sound natural sources,
namely crab and shrimp shell wastes.
• Together with chitin, Chitosan is well thought-out the
second most profuse polysaccharide subsequent to
cellulose.
• Chitosan is derived by the alkaline deacetylation of chitin
• Chitin is an amino polysaccharide (combination of sugar
and protein).
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24. • CHEMISTRY
• Chitosan is chemically (Poly[-(1, 4)-2-amino-2-deoxy-D-
glucopiranose])
• Chitosan isolated from shells of shrimp, crab and lobster by
treating the shells with 2.5 N NaOH at 750°C and with 1.7 N
HCl at room temperature for 6 hours
• The polymer differs from chitin in that a majority of the N-
acetyl groups in Chitosan is hydrolyzed.
• The degree of hydrolysis has a significant effect on the
solubility and rheological properties of the polymer.
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25. • APPLICATIONS
• GENERAL PHARMACEUTICAL APPLICATIONS OF CHITOSAN
a) Chitosan by itself is haemostatic (stops bleeding), some
derivatives such as sulphated Chitosan are anticoagulants. By
utilizing the haemostatic effect, Chitosan bandages and sponges
we prepared for surgical treatment and wound protection.
b) It has a capacity of forming film and has been suggested as a
biopolymer of choice for the development of contact lenses (soft
and hard contact lenses).
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26. c) It has been used for the manufacturing of ocular bandage
lenses used a protective device for acutely or chronically
traumatized eyes.
d) It is also useful as artificial kidney membranes because of
their suitable permeability and high tensile strength.
e) Used in antacids and antiulcer drugs, wound and burn healing
properties, immobilization of enzymes and living cell and in
ophthalmology.
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27. Amongthepharmaceuticalapplicationsithasbeenused
asa:
1. Diluents in direct compression of tablets.
2. Binder in wet granulation
3. Slow-release of drugs from tablets and granules
4. Drug carrier in micro particle systems
5. Films controlling drug release
6. Preparation of hydrogels.
7. Wetting agent And Disintegrant
8. Agent for increasing viscosity in solutions.
9. Bio adhesive polymer
10. Site-specific drug delivery (e.g. to the stomach or colon)
11. Absorption enhancer (e.g. for nasal or oral drug delivery)
12. Carrier in relation to vaccine delivery or gene therapy 27

28. • Conclusion
• Biodegradable polymer are naturally degradable polymer
widely use in pharmaceutical formulation.
• Biopolymers limit carbon dioxide emissions during creation,
and degrade to organic matter after disposal.
• Biodegradable polymers have received much more attention
in the last decades due their potential applications in the
fields related to environmental protection and the
maintenance of physical health.
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29. • To improve the properties of biodegradable polymers, a lot of
methods have been developed, such as block copolymerization
or grafting. These methods improve both the biodegradation
rate and the mechanical properties of the final products.
• Physical blending is another route to prepare biodegradable
materials with different morphologies and physical
characteristics.
• Recently different studies have been reported concerning the
use of nanoclay with biodegradable polymers, especially with
starch.
• Nano-biocomposites or bio-nanocomposites are under
investigation.
• Bio-polymers hold great promises for formulation
development in future.
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30. • References
1. N. K. Jain,2005, “Progress in controlled and novel drug delivery
systems” CBS Publishers and Distributors , Pg no.11-14.
2. S.P. Vyas, Roop K. Khar, 2002, “Controlled drug delivery : Concept
and Advances”, Vallabh Prakashan, Pg.no.97-151.
3. Sangamesh Kumbhar, et.al., 2014, “Natural and synthetic
biomedical polymers”, Elsevier publication, Pg.no.280-285.
4. Ashwin Kumar, et.al., 2011, “Biodegradable Polymers and Its
Applications” , International Journal of Bioscience, Biochemistry
and Bioinformatics, Vol.3,Pg.no.173- 176.
5. Isabelle Vroman and Lan Tighzert,2009, “Biodegradable Polymers”,
Science & medicine,Vol.2, Pg.no.307-344.
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31. 6. Laxmi S. Nair, et.al., 2007, “Biodegradable polymer as
biomaterial”, Science direct, Elsevier publication, Pg.no.762-798.
7. K. Kavitha, et.al., 2011, “Chitosan polymer as carrier in various
pharmaceutical formulation : brief review”, International Journal
of Applied Biology and Pharmaceutical Technology,
Vol.2,Pg.no.249-258.
8. Angelica Diaz, et.al., 2014, “Synthesis, Properties and Applications
of Biodegradable Polymers Derived from Diols and Dicarboxylic
Acids: From Polyesters to Poly(ester amide)s’”, International
Journal of Molecular Sciences, Pg.no.7064-7123.
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