2. Biodegradable Polymers as Drug
Carrier Systems
• Polyesters
– Lactide/Glycolide Copolymers
• Have been used for the delivery of steriods,
anticancer agent, antibiotics, etc.
• PLLA is found as an excellent biomaterials and
safe for in vivo (Lactic acid contains an asymmetric
α-carbon atom with three different isomers as D-,
L- and DL-lactic acid)
• PLGA is most widely investigated biodegradable
polymers for drug delivery.
• Lactide/glycolide copolymers have been subjected
to extensive animal and human trials without any
significant harmful side effects
3. • Poly(amides)
– Natural Polymers
• Remain attractive because they are natural
products of living organism, readily available,
relatively inexpensive, etc.
• Mostly focused on the use of proteins such as
gelatin, collagen, and albumin
Biodegradable Polymers as Drug
Carrier Systems
4. • Polymer Processing
– Drug-incorporated matrices can be formulated
either compression or injection molding
– Polymer & drug can be ground in a Micro Mill,
sieve into particle size of 90-120 µm, then
press into circular disc
– Alternatively drug can be mixed into molten
polymer to form small chips, then it is fed into
injection molder to mold into desired shape
Biodegradable Polymers as Drug
Carrier Systems
5. • Why nanoparticles are desired for drug
delivery system?
Biodegradable Polymers as Drug
Carrier Systems
6. • Nanoparticles can be used to increase drug
solubility, have lower toxicity & target drug
delivery
• In order to use nanoparticle as drug delivery,
they must satisfy number of criteria;
– Biocompatible
– Good drug payload
– Manufacturing cost must be reasonable
Biodegradable Polymers as Drug
Carrier Systems
7. Polymer for Dental Application
• Four main groups of materials used in
dentistry;
– Metal and alloys
– Ceramics
– Synthetic organic polymers & biopolymers
(derived from natural tissues)
– Composites (an organic matrix polymers filled
with inorganic fine particles)
8. • In 19th century, gutth-percha was used for
filling
• In 1909, PMMA was used as artificial teeth
filling
• In 1930s, polyamide, polyester,
polyethylene were prepared in different
forms (rigid, soft, fibers, adhesives, etc) for
several applications (filling, implant,
sutures, etc)
Polymer for Dental Application
10. • Bases, liners and varnishes for cavities
– There is a large diversity or organic and
inorganic materials for this purposes
– Zinc polycarboxylate (or polyacrylate) cement
is prepared by mixing zinc oxide and the
polymer solution, and water solution of
polyacrylic acid
Polymer for Dental Application
11. • Filling & Restorative Materials
– Made up of organic matrix and inorganic
particulate or fibrous filling. Held together by
coupling agent
– PMMA resins have been used as filling
materials, but they have several
disadvantages
• Nonadhesion to dental structures
• Low colour stability
• Low molecular weight of monomer
• High polymerization shrinkage
Polymer for Dental Application
12. • 2000 BC, natural fibers like linen, silk, horsehair
were used as suture materials
• After world war II revolution of medical textile,
used of steel wire and synthetic fibers (PP,
nylon, polyester)
• In early 1970s, two synthetic absorbable wound
closure biomaterials, i.e. Dexon & Vicyrl were
introduced
• The four most widely used textile structure;
woven, knitted, nonwoven and braided
Textile based Biomaterials for
Surgical Application
14. • Wound closure biomaterials are divided
into;
– Suture materials
– Tissue adhesives
– staplers
Textile based Biomaterials for
Surgical Application
15. • Suture- is a strand of textile materials (natural or
synthetic), used to ligate blood vessel and draw
tissue together
• Ideal suture should
– Physical and mechanical properties (adequate tensile
strength, etc)
– Handling properties (easy to handle)
– Biological properties (unfavourable for bacterial
growth)
– Biodegradation properties (absorbable; its tensile
strength loss must match the healing rate of the tissue
to be closed)
Textile based Biomaterials for
Surgical Application
17. • Suture materials can be classified into 2
broad categories;
– Absorbable;loss their entire tensile strength
within two to three months
– Nonabsorbable; retain their strength longer
than two to three months
Textile based Biomaterials for
Surgical Application
18. Biocompatibility of Elastomer
• Elastomer-definition
– Flexible- i.e.have low rigidity
– Highly deformable, i.e. able to withstand
strong deforming forces without rupturing and
have elongation at rupture over 200%
– Elastic or resilient, i.e. able to return to their
original shape and size after deforming forces
is removed
19. • Various famililes of Elastomers
– General-use elastomer- natural rubber (NR),
styrene butadiene rubber (SBR), etc
– Special elastomer- ethylene propylene and
diene copolymer (EPM, EPDM), nitrile
butadiene copolymer (NBR)
– Very special elastomers- high thermal and/or
chemical resistance elastomer-
fluoroelastomer, silicone elastomer, etc
– Thermoplastic elastomer
Biocompatibility of Elastomer
20. • Silicone elastomer
– Widely used because it is strong, very mobile
bone of their Si-O-Si (siloxane) caternary
backbone; which provide chemical inertness
and flexibility, stable over time at a body
temp., show little tissue reactivity, and highly
resistant to chemical attack and heat.
Biocompatibility of Elastomer
