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Polymer for Medical Applications


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

Polymer for Medical Applications
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

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

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

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

Biodegradable Polymers as Drug Carrier Systems
  • Nanoparticles can be used to increase drug
    solubility, have lower toxicity target drug
  • In order to use nanoparticle as drug delivery,
    they must satisfy number of criteria
  • Biocompatible
  • Good drug payload
  • Manufacturing cost must be reasonable

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)

Polymer for Dental Application
  • In 19th century, gutth-percha was used for
  • In 1909, PMMA was used as artificial teeth
  • In 1930s, polyamide, polyester, polyethylene were
    prepared in different forms (rigid, soft, fibers,
    adhesives, etc) for several applications
    (filling, implant, sutures, etc)

Schematic of different area of chemistry
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

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

Textile based Biomaterials for Surgical
  • 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
  • The four most widely used textile structure
    woven, knitted, nonwoven and braided

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

Textile based Biomaterials for Surgical
  • 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
  • Biodegradation properties (absorbable its
    tensile strength loss must match the healing rate
    of the tissue to be closed)

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

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

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

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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