Polymers and Their Classification
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Questions and Answers

What is the result of incorporating a solvent into the structure of polymers?

  • Formation of a crystal
  • Breakdown of the polymer
  • Creation of a new polymer
  • Formation of a gel (correct)
  • What is the purpose of polymers as film coatings in pharmaceutical applications?

  • To mask the unpleasant taste of a drug (correct)
  • To modify drug release characteristics
  • To enhance drug stability
  • To create a crystalline structure
  • Which of the following is NOT a characteristic of an ideal polymer system?

  • Good mechanical strength
  • Toxic (correct)
  • Inert and compatible with the environment
  • Easily administrable
  • What is an example of a polymer-based technology in drug delivery?

    <p>Controlled release</p> Signup and view all the answers

    What type of polymers are rarely 100% crystalline?

    <p>Crystalline polymers</p> Signup and view all the answers

    What is the role of polymers in pharmaceutical applications?

    <p>To control viscosity and flow</p> Signup and view all the answers

    What is the meaning of the word 'polymer'?

    <p>Many parts</p> Signup and view all the answers

    What is the main difference between homopolymers and copolymers?

    <p>Homopolymers have identical monomer units</p> Signup and view all the answers

    What is the effect of cross-linking on the solubility of a polymer?

    <p>It decreases the solubility</p> Signup and view all the answers

    What is the characteristic of a highly cross-linked polymer?

    <p>It is highly rigid</p> Signup and view all the answers

    What is the reason why highly cross-linked polymers do not melt?

    <p>They degrade at high temperatures before their chains start to move</p> Signup and view all the answers

    What is the characteristic of linear polymers?

    <p>They have a high melting temperature</p> Signup and view all the answers

    What is the characteristic of branched polymers?

    <p>They have a low melting temperature</p> Signup and view all the answers

    What is formed when cross-linked polymers are added to solvents?

    <p>A gel</p> Signup and view all the answers

    Study Notes

    Polymers

    • Polymers are substances of high molecular weight made up of repeating monomer units.
    • Examples of polymers include proteins (monomer is amino acid) and polysaccharide (monomer is saccharide).
    • The word "polymer" means "many parts".

    Polymer Categories

    • Polymers can be classified based on composition, with homopolymers having identical monomeric units and copolymers having more than one monomer type.
    • Polymers can also be classified based on linkage and structure, with characteristics such as:
      • Linear or Branched
      • Crosslinking or not
      • Crystalline or amorphous
      • Entangled polymers with secondary bonding

    Branched or Linear Polymers

    • Polymers can be branched or linear, with branched polymers forming networks and having a low melting temperature.
    • Linear chains have a higher chance of approaching each other in their solid state, increasing their crystallinity and melting temperature.

    Polymer Crosslinking

    • Linear or branched chains may be joined by crosslinks, restricting their movement and increasing their rigidity.
    • Highly cross-linked polymers are very rigid (three-dimensional) structures that degrade at high temperatures before their chains start to move.
    • Crosslinking sacrifices solubility for swellability.

    Gels

    • Gels are formed when crosslinked polymers are added to solvents (such as water), causing the polymers to swell but not dissolve.
    • The incorporation of the solvent into the polymer structure leads to the formation of the gel.
    • Polymers used to prepare gels are called gelling agents (e.g., carbapol).

    Crystalline and Amorphous Polymers

    • Polymers are rarely 100% crystalline, as it is difficult for all regions of all chains to become aligned.
    • Crystalline regions are typically found alongside amorphous regions.

    Pharmaceutical Applications of Polymers

    • Polymers have a range of pharmaceutical applications, including:
      • Binders in tablets
      • Viscosity and flow controlling agents in liquids, suspensions, and emulsions
      • Film coatings to mask unpleasant tastes
      • Enhancing drug stability
      • Modifying drug release characteristics (e.g., controlled release, targeted release, and improved bioavailability)

    Characteristics of Ideal Polymer System

    • Inert and compatible with the environment
    • Nontoxic
    • Easily administrable
    • Easy and inexpensive to fabricate the dosage form
    • Good mechanical strength

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    Related Documents

    Polymers PDF

    Description

    Learn about polymers, their composition, and classification. Discover the differences between homopolymers and copolymers and explore their structures.

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