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Polymer for Medical Applications

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Polymer for Medical Applications Biodegradable Polymers as Drug Carrier Systems Polyesters Lactide/Glycolide Copolymers Have been used for the delivery of steriods ... – PowerPoint PPT presentation

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Title: Polymer for Medical Applications


1
Polymer for Medical Applications
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 a-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
Biodegradable Polymers as Drug Carrier Systems
  • 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

4
Biodegradable Polymers as Drug Carrier Systems
  • 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 ┬Ám, 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

5
Biodegradable Polymers as Drug Carrier Systems
  • Why nanoparticles are desired for drug delivery
    system?

6
Biodegradable Polymers as Drug Carrier Systems
  • 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

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
Polymer for Dental Application
  • 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)

9
Schematic of different area of chemistry
10
Polymer for Dental Application
  • 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

11
Polymer for Dental Application
  • 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

12
Textile based Biomaterials for Surgical
Application
  • 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

13
Commercial Suture materials
Multifilament nylon
Braided Polyester
Polythetrafluoroethylene
14
Textile based Biomaterials for Surgical
Application
  • Wound closure biomaterials are divided into
  • Suture materials
  • Tissue adhesives
  • staplers

15
Textile based Biomaterials for Surgical
Application
  • 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)

16
Table of Relative Tissue Reactivity to Sutures
17
Textile based Biomaterials for Surgical
Application
  • Suture materials can be classified into 2 broad
    categories
  • Absorbableloss their entire tensile strength
    within two to three months
  • Nonabsorbable retain their strength longer than
    two to three months

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
Biocompatibility of Elastomer
  • 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

20
Biocompatibility of Elastomer
  • 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.

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Medical device in human body
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