Pharm II Drug Formulation Properties Preservatives Quiz
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Questions and Answers

Which chemical preservative is known for its contact sensitivity and allergic reactions?

  • Mercurials
  • Alcohols
  • Thimerosal (correct)
  • Chlorobutanol

    • What is the main reason for the rare prescription of Thimerosal?

  • Low effectiveness
  • Alcohol content
  • Contact sensitivity (correct)
  • High cost

    • Which chemical preservative is described as being less effective as an antimicrobial?

  • Chlorobutanol (correct)
  • EDTA
  • Alcohols
  • BAC (Benzalkonium Chloride)

    • What is the main advantage of combining EDTA with a preservative?

    <p>Enhances antimicrobial effect</p> Signup and view all the answers

    Which chemical preservative undergoes conversion to hydrogen peroxide and then to oxygen and water when in contact with the eye?

    <p>Sodium Perborate</p> Signup and view all the answers

    What is the fate of Stabilized Oxychloro Complex (Purite) upon light exposure?

    <p>It dissipates into water and sodium chloride</p> Signup and view all the answers

    What additional component is mentioned to make Alcohols more effective as a preservative?

    <p>EDTA</p> Signup and view all the answers

    What kind of reactions are very common with Mercurials?

    <p>Allergic reactions</p> Signup and view all the answers

    What happens when Sodium Perborate comes in contact with the eye?

    <p>It transforms into a different chemical compound</p> Signup and view all the answers

    What is the purpose of using viscous agents in ocular drug administration?

    <p>To increase the viscosity of the drug for more staying power on the ocular surface</p> Signup and view all the answers

    Which excipient is used to give an ophthalmic solution the property of resisting a change in pH?

    <p>Potassium and sodium bicarbonate</p> Signup and view all the answers

    What is the purpose of using tonicity agents in ocular drug formulations?

    <p>To increase the osmotic pressure or tension of a solution</p> Signup and view all the answers

    Which statement best describes the function of gel-forming systems in ocular drug administration?

    <p>They reversibly gel on contact with the precorneal tear film, leading to longer contact time and prolonged drug action</p> Signup and view all the answers

    What is the purpose of using Amberlite-Cation Exchange Resin in ocular drug formulations?

    <p>To bind with the drug, reducing free drug in solution and enhancing stability</p> Signup and view all the answers

    What effect does carbopol gel have when combined with a cation exchange resin in ocular drug formulations?

    <p>It increases viscosity and contact time</p> Signup and view all the answers

    What is the main purpose of polyacrylic acids in ocular drug vehicles?

    <p>To decrease viscosity with an increase in shear rate</p> Signup and view all the answers

    What do ointments and punctal plugs serve as examples of in ocular drug delivery?

    <p>Drug release systems</p> Signup and view all the answers

    What is the purpose of using hydroxypropyl methylcellulose in ocular drug vehicles?

    <p>To reversibly gel on contact with precorneal tear film</p> Signup and view all the answers

    What do large molecules in gel-forming systems do when they come into contact with precorneal tear film?

    <p>They reversibly gel, leading to longer contact time and prolonged drug action</p> Signup and view all the answers

    What effect does Gelrite, a polysaccharide, have in ocular drug formulation?

    <p>Reversibly gels in presence of mono/divalent cations, enhancing corneal penetration and prolonging drug action</p> Signup and view all the answers

    What is the mechanism of action of stabilized oxychloro complex (Purite®) as a preservative in ocular lubricants?

    <p>It breaks down into water, oxygen, sodium, and chlorine free radicals when exposed to light, which inhibits microbial protein synthesis within cells.</p> Signup and view all the answers

    What is the main function of sodium perborate as a preservative in ocular lubricants?

    <p>It catalyzes into hydrogen peroxide when combined with water, which leads to the killing of microbes.</p> Signup and view all the answers

    Which statement accurately describes the mechanism of action of methylparaben and propylparaben as preservatives in ocular lubricants?

    <p>They act as chelating agents by chelating calcium for cell junction formation.</p> Signup and view all the answers

    What is the role of EDTA (ethylenediaminetetraacetic acid) as a preservative in ocular lubricants?

    <p>Chelates calcium for cell junction formation.</p> Signup and view all the answers

    What is the primary mechanism by which chlorobutanol acts as a preservative in ocular lubricants?

    <p>It disrupts the lipid component of the bacterial cell membrane, causing cell lysis via alteration of microbial cell membrane lipid configuration.</p> Signup and view all the answers

    What distinguishes polysorbate 80 from BAK (Benzalkonium chloride) in terms of its mechanism as a preservative in ocular lubricants?

    Signup and view all the answers

    What is the primary function of Polyquaternium-1 (Polyquad) as a preservative in ocular lubricants?

    <p>'Polyquaternium-1 (Polyquad) has limited antimicrobial activity and inhibits microbial growth via acidification.'</p> Signup and view all the answers

    'SofZia' is considered less toxic than BAK (Benzalkonium chloride). What makes it less toxic compared to BAK?

    Signup and view all the answers

    What is the primary function of tonicity agents in ocular drug formulations?

    <p>To increase the osmotic pressure of the solution</p> Signup and view all the answers

    What is the mechanism of action of Gelrite, a polysaccharide, in ocular drug formulations?

    <p>It prolongs the drug action</p> Signup and view all the answers

    What is the primary purpose of using polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) in ocular drug vehicles?

    <p>To decrease viscosity with increased shear rate</p> Signup and view all the answers

    What characteristic is associated with vehicles utilizing gel-forming systems in ocular drug formulations?

    <p>They exhibit reversible phase transitions</p> Signup and view all the answers

    What is the role of Amberlite-Cation Exchange Resin in ocular drug formulations?

    <p>To reduce free drug in solution and enhance comfort</p> Signup and view all the answers

    What happens when Amberlite-Cation Exchange Resin comes into contact with tears in ocular drug formulations?

    <p>It reduces free drug in solution and enhances comfort</p> Signup and view all the answers

    What is the primary function of carbopol gel when combined with a cation exchange resin in ocular drug formulations?

    <p>To enhance stability and resuspendability of the drug</p> Signup and view all the answers

    What is the main purpose of using viscous agents in ocular drug administration?

    <p>To allow more staying power on the ocular surface</p> Signup and view all the answers

    What effect does combining EDTA with a preservative have in ocular drug formulations?

    <p>Enhances stability and resuspendability of the drug</p> Signup and view all the answers

    What is the primary mechanism by which stabilized oxychloro complex (Purite®) acts as a preservative in ocular lubricants?

    <p>Undergoes conversion to sodium chloride and then to oxygen and water when in contact with the eye</p> Signup and view all the answers

    What do ointments and punctal plugs serve as examples of in ocular drug delivery?

    <p>Drug release systems</p> Signup and view all the answers

    What is the main function of sodium perborate as a preservative in ocular lubricants?

    <p>Undergoes conversion to hydrogen peroxide and then to oxygen and water when in contact with the eye</p> Signup and view all the answers

    What is the primary mechanism of action of sodium perborate as a preservative in ocular lubricants?

    <p>Catalyzing into hydrogen peroxide, water, and oxygen when in contact with the eye</p> Signup and view all the answers

    What is the main function of EDTA (ethylenediaminetetraacetic acid) as a preservative in ocular lubricants?

    <p>Chelating calcium for cell junction formation</p> Signup and view all the answers

    What is the primary reason for the rare prescription of Thimerosal in ocular drug formulations?

    <p>It is highly toxic and can lead to contact dermatitis</p> Signup and view all the answers

    What distinguishes polysorbate 80 from BAK (Benzalkonium chloride) in terms of its mechanism as a preservative in ocular lubricants?

    <p>Causing bacterial cell death by interrupting the lipid component of the cell membrane</p> Signup and view all the answers

    What is the role of EDTA (ethylenediaminetetraacetic acid) as a preservative in ocular lubricants?

    <p>Chelating calcium for cell junction formation</p> Signup and view all the answers

    'SofZia' is considered less toxic than BAK (Benzalkonium chloride). What makes it less toxic compared to BAK?

    <p>It dissociates into water, oxygen, sodium, and chlorine free radicals in the presence of light</p> Signup and view all the answers

    Which chemical preservative is known for its contact sensitivity and allergic reactions?

    <p>Thimersol</p> Signup and view all the answers

    'SofZia' is considered less toxic than BAK (Benzalkonium chloride). What makes it less toxic compared to BAK?

    <p>It dissociates into water, oxygen, sodium, and chlorine free radicals in the presence of light</p> Signup and view all the answers

    What effect does Gelrite, a polysaccharide, have in ocular drug formulation?

    <p>Increasing viscosity to delay washout and increase drug bioavailability</p> Signup and view all the answers

    Which chemical preservative is described as being less effective as an antimicrobial?

    <p>Chlorobutanol</p> Signup and view all the answers

    What is the primary function of Polyquaternium-1 (Polyquad) as a preservative in ocular lubricants?

    <p>Damages bacterial cytoplasmic membrane, with leakage of cell contents as well as causes coagulation of cytoplasm</p> Signup and view all the answers

    What is the primary function of the chemical preservative Thimerosal in ocular lubricants?

    <p>To cause contact sensitivity and allergic reactions</p> Signup and view all the answers

    What additional component is mentioned to make alcohols more effective as a preservative in ocular lubricants?

    <p>EDTA (Ethylenediaminetetraacetic acid)</p> Signup and view all the answers

    What is the mechanism of action of Stabilized Oxychloro Complex (Purite) as a preservative in ocular lubricants?

    <p>It dissipates into water and sodium chloride upon light exposure</p> Signup and view all the answers

    Which chemical preservative is known for its contact sensitivity and allergic reactions?

    <p>Thimerosal</p> Signup and view all the answers

    What is the primary function of sodium perborate as a preservative in ocular lubricants?

    <p>To convert to hydrogen peroxide and then oxygen and water in eye contact</p> Signup and view all the answers

    What distinguishes polysorbate 80 from BAK (Benzalkonium chloride) in terms of its mechanism as a preservative in ocular lubricants?

    <p>Polysorbate 80 is less effective as an antimicrobial agent</p> Signup and view all the answers

    What is the role of EDTA (Ethylenediaminetetraacetic acid) as a component in ocular drug formulations?

    <p>To help alcohols become more effective as a preservative</p> Signup and view all the answers

    What do large molecules in gel-forming systems do when they come into contact with precorneal tear film?

    <p>They form a protective layer over the corneal surface</p> Signup and view all the answers

    What is the main advantage of combining EDTA with a preservative in ocular drug formulations?

    <p>More effective as an antimicrobial agent</p> Signup and view all the answers

    What effect does Gelrite, a polysaccharide, have in ocular drug formulation?

    <p>It forms a protective layer over the corneal surface when combined with precorneal tear film</p> Signup and view all the answers

    What is the main reason for the rare prescription of Thimerosal?

    <p>It leads to common contact sensitivity and allergic reactions</p> Signup and view all the answers

    What is the fate of Stabilized Oxychloro Complex (Purite) upon light exposure?

    <p>It dissipates into water and sodium chloride upon light exposure</p> Signup and view all the answers

    Study Notes

    Chemical Preservatives and Their Impact

    • Thimerosal: Known for causing contact sensitivity and allergic reactions; rare prescription due to concerns over mercury exposure.
    • Sodium Perborate: Converts to hydrogen peroxide and subsequently decomposes to oxygen and water upon contact with the eye.
    • Polyquaternium-1 (Polyquad): Serves as a preservative in ocular lubricants primarily to reduce microbial growth.
    • EDTA (Ethylenediaminetetraacetic acid): Functions as a preservative by chelating metal ions that could promote microbial growth; combining with preservatives enhances their efficacy.
    • Alcohols: Effectiveness as a preservative is improved when combined with other compounds such as glycerin.
    • Stabilized Oxychloro Complex (Purite): Acts by converting into non-toxic byproducts upon light exposure, rendering it safe in ocular applications.

    Mechanisms and Effects in Ocular Drug Formulations

    • Viscous Agents: Used to enhance the retention time of drugs in the ocular surface, improving therapeutic effects.
    • Tonicity Agents: Ensure that ocular formulations are isotonic with tear film, reducing discomfort upon application.
    • Gel-forming Systems: Provide sustained release of drugs and enhance ocular contact time due to increased viscosity.
    • Amberlite-Cation Exchange Resin: Regulates osmotic balance and drug release in ocular formulations; interacts with tears upon contact, affecting dispersion.
    • Carbopol Gel: When combined with cation exchange resins, it maintains viscosity and improves drug delivery efficiency.

    Safety and Efficacy of Preservatives

    • SofZia: Reputed to be less toxic compared to Benzalkonium chloride due to its rapid breakdown products and reduced irritancy.
    • Gelrite: A polysaccharide that forms a gel upon contact with precorneal tear film, enhancing drug retention and release.
    • Mercurials: Known for frequent allergic reactions, limiting their use in ocular applications due to patient sensitivity.

    Overview of Specific Agents

    • Polysorbate 80 vs. BAK: Distinguishable by their respective mechanisms; polysorbate is less irritating and offers better biocompatibility.
    • Sodium Perborate: Besides its preservative role, it has a primary function of providing a stable release of active ingredients in ocular lubricants.
    • Polyvinyl Alcohol (PVA) and Polyvinylpyrrolidone (PVP): These are utilized to provide viscosity and improve the stability of ocular formulations.

    Conclusion

    • Understanding the different chemical preservatives and their mechanisms is crucial for formulating effective ocular drugs with minimized adverse reactions and enhanced patient safety.

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    Lecture 1 Principles of Oc Drug Administration PDF

    Description

    Test your knowledge of drug formulation properties and preservatives used in ocular drug administration, including chemical preservatives like mercurials and detergents like alcohols. Explore the rare use of thimerosal due to allergic reactions and the effectiveness of chlorobutanol as an antimicrobial agent.

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