Suppository Bases in Pharmacology
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Questions and Answers

What is the melting point range of Polyoxyl 40 stearate?

  • 39°C to 45°C (correct)
  • 60°C to 65°C
  • 25°C to 30°C
  • 50°C to 55°C

    • Which of the following bases may require lubrication for mold release?

  • Polyoxyl 40 stearate
  • Glycerinated gelatin (correct)
  • Cocoa butter
  • Polyethylene glycol

    • What type of emulsion is typically seen among the miscellaneous bases?

  • Water-in-oil type (correct)
  • Oil-in-water type
  • Solid-in-liquid type
  • Water-in-solid type

    • Why may different bases prepared in the same mold yield different weights of suppositories?

    <p>There is a difference in the densities of the materials.</p> Signup and view all the answers

    Which of the following materials is noted as both oleaginous and water-miscible?

    <p>Polyoxyl 40 stearate</p> Signup and view all the answers

    What is the main constituent of cocoa butter?

    <p>Triglyceride derived from palmitic, stearic, and oleic acids</p> Signup and view all the answers

    At what temperature does cocoa butter typically melt?

    <p>30°C to 36°C</p> Signup and view all the answers

    Which of the following is a consequence of hastily melting cocoa butter?

    <p>Formation of unstable alpha crystals with a low melting point</p> Signup and view all the answers

    What is the recommended method for melting cocoa butter to avoid unstable crystalline forms?

    <p>Slowly and evenly over a warm water bath</p> Signup and view all the answers

    Which agents can lower the melting point of cocoa butter?

    <p>Phenol and chloral hydrate</p> Signup and view all the answers

    What percentage of cetyl esters wax is typically added to cocoa butter to solidify it?

    <p>20%</p> Signup and view all the answers

    What is a risk associated with adding too much hardening agent to cocoa butter?

    <p>It prevents the base from melting in the body</p> Signup and view all the answers

    Why is cocoa butter preferred as a suppository base?

    <p>It melts at body temperature yet solidifies normally</p> Signup and view all the answers

    What is the main reason glycerinated gelatin suppositories are commonly used in vaginal preparations?

    <p>They provide prolonged local action of the medicinal agent.</p> Signup and view all the answers

    Which factor affects the stiffness of glycerinated gelatin suppositories?

    <p>The proportion of gelatin used.</p> Signup and view all the answers

    What is a disadvantage of using a glycerinated gelatin base for suppositories?

    <p>They can irritate tissues upon insertion.</p> Signup and view all the answers

    How does polyethylene glycol (PEG) compare in its thermal characteristics to other suppository bases?

    <p>PEGs dissolve slowly rather than melting.</p> Signup and view all the answers

    What must be done to PEG suppositories that do not contain at least 20% water before insertion?

    <p>They need to be dipped in water.</p> Signup and view all the answers

    What happens when glycerinated gelatin suppositories are stored improperly due to their hygroscopic nature?

    <p>They can absorb moisture from the air.</p> Signup and view all the answers

    What is the relationship between the molecular weight of polyethylene glycols (PEGs) and their hardness?

    <p>Hardness increases with increased molecular weight.</p> Signup and view all the answers

    What is a primary benefit of polyethylene glycol suppositories in terms of their physical characteristics?

    <p>They maintain a solid state, allowing easy handling.</p> Signup and view all the answers

    Which characteristic is essential for a suppository base?

    <p>It should remain solid at room temperature but soften at body temperature.</p> Signup and view all the answers

    What is one disadvantage of using cocoa butter as a suppository base for fat-soluble drugs?

    <p>Fat-soluble drugs tend to remain in the oil phase.</p> Signup and view all the answers

    Which property of glycerinated gelatin and polyethylene glycol influences drug release in suppositories?

    <p>They dissolve slowly in body fluids.</p> Signup and view all the answers

    Which of the following is true about un-ionized drugs in suppositories?

    <p>They partition out of water-miscible bases quickly.</p> Signup and view all the answers

    What is an advantage of using water-soluble bases for fat-soluble drugs?

    <p>They enhance the release of fat-soluble drugs.</p> Signup and view all the answers

    Which of these substances is NOT classified as a fatty or oleaginous base?

    <p>Polyethylene glycol</p> Signup and view all the answers

    What is the recommended form of drug to use with a cocoa butter base for optimal bioavailability?

    <p>Ionized (salt) form</p> Signup and view all the answers

    Which of the following oils is recommended as a substitute for cocoa butter?

    <p>Cottonseed oil</p> Signup and view all the answers

    Study Notes

    Suppository Bases

    • Suppository bases must be solid at room temperature but melt or dissolve at body temperature for drug release.
    • Fatty bases (Oleaginous) - Cocoa butter, hydrogenated fatty acids of vegetable oils (palm kernel oil, cottonseed oil), fat-based compounds (glyceryl monostearate, glyceryl monopalmitate
      • Cocoa butter: ideal base, melts just below body temperature, but may exhibit polymorphism (multiple crystal forms)
        • To avoid unstable crystal formation (alpha), melt slowly and evenly over warm water
        • Substances like phenol and chloral hydrate can lower melting point, requiring solidifying agents (cetyl esters wax or beeswax)
    • Water-Soluble or Water-Miscible Bases: Glycerinated gelatin, Polyethylene glycols (PEGs)
      • Glycerinated Gelatin: Gelatin dissolved in glycerin and water, used for prolonged local action (vaginal suppositories).
        • Disadvantages: Laxative effect of glycerol, hygroscopic (absorbs moisture), can irritate tissues upon insertion
      • PEGs: Polymers of ethylene oxide and water, come in various chain lengths and molecular weights.
        • Hardness increases with molecular weight
        • Do not melt at body temperature, but dissolve slowly
        • Can be formulated with higher melting points for slower release and convenient storage.
    • Miscellaneous Bases: Combinations of lipophilic and hydrophilic substances
      • Example: Polyoxyl 40 stearate (water-soluble, melting point of 39°C - 45°C)

    Effect of Drug Ionization and Suppository Base on Release

    • Un-ionized Drugs (HB): More readily partition out of water-miscible bases (glycerinated gelatin, PEG). But, bases dissolve slowly, retarding release.
    • Ionized Drugs (B-): For systemic action, using a cocoa butter base, it's better to incorporate the ionized (salt) form for better bioavailability.

    Preparation of Suppositories

    • Calibration of the Mold: Each mold has a specific volume. Different bases will have varying weights in the same mold due to density differences.
    • Lubrication of the Mold: May be needed to facilitate removal of molded suppositories.
      • Not usually needed with cocoa butter or PEG bases
      • Usually needed for glycerinated gelatin (use a thin coating of mineral oil)

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    Related Documents

    Pharmaceutics Lecture 6: Suppositories PDF

    Description

    Explore the different types of suppository bases, including fatty and water-soluble options. Understand the properties and applications of each base, particularly in drug delivery systems. This quiz helps reinforce knowledge related to the formulation of suppositories in pharmacology.

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