Ophthalmic Drug Delivery and Dosage Forms
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Questions and Answers

What should a patient do to minimize taste and drainage after instilling eye drops?

  • Use a cotton ball to absorb excess liquid.
  • Keep the eye open for as long as possible.
  • Apply pressure to the inner corner of the eye for 30 seconds. (correct)
  • Gently blow the nose immediately after application.

    • When administering eye drops and ointments, what is the recommended order and time interval?

  • Ointment first, followed by drops after 5 minutes.
  • Drops first, followed by ointment after 10 minutes. (correct)
  • Ointment should not be used if drops are applied.
  • Drops and ointments can be applied simultaneously.

    • What is a critical guideline for the storage of eye drop products?

  • Most products should be kept in direct sunlight.
  • Certain eye drops may require refrigeration as specified. (correct)
  • All eye drops must be stored in a freezer.
  • Eye drops should be stored at room temperature regardless of the product.

    • What is a major pathway for ophthalmic drug absorption into systemic circulation?

    <p>Nasolacrimal drainage into the nasal cavity</p> Signup and view all the answers

    What action should be taken if multi-dose eye drops show signs of contamination?

    <p>Dispose of the product within 30 days of opening.</p> Signup and view all the answers

    Which of the following is NOT recommended when administering eye ointment?

    <p>Squeezing a ribbon of ointment directly into the eye.</p> Signup and view all the answers

    Which factor is NOT considered key in designing topical ophthalmic dosage forms?

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

    What is the consequence of contamination in ophthalmic products?

    <p>Risk of serious complications including blindness</p> Signup and view all the answers

    Which preservative is most commonly used in multi-dose eye drops?

    <p>Benzalkonium Chloride (BAK)</p> Signup and view all the answers

    Which statement about the GI tract absorption pathway for ophthalmic drugs is accurate?

    <p>Drugs reaching the nasopharynx can be swallowed leading to GI absorption.</p> Signup and view all the answers

    Why do single-use eye drops not require preservatives?

    <p>They are designed for immediate use and do not last long.</p> Signup and view all the answers

    What is a potential drawback of using Benzalkonium Chloride (BAK) as a preservative?

    <p>Risk of corneal epithelium damage at high concentrations</p> Signup and view all the answers

    What percentage of an instilled ophthalmic dose can potentially be systemically absorbed?

    <p>More than 50%</p> Signup and view all the answers

    Which preservative has seen a decline in use due to hypersensitivity concerns?

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

    What is the ideal pH range for an ophthalmic product to avoid eye irritation?

    <p>6.6 - 7.8</p> Signup and view all the answers

    What osmolarity is generally considered isotonic for ophthalmic formulations?

    <p>300 mOsm/kg</p> Signup and view all the answers

    Which of the following viscosity modifiers is NOT commonly used in ophthalmic formulations?

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

    What role do buffers play in ophthalmic formulations?

    <p>Adjust pH for stability and patient comfort</p> Signup and view all the answers

    Which ingredient is intentionally hypertonic for treating corneal edema?

    <p>Sodium chloride 5%</p> Signup and view all the answers

    What potential issue can arise from using excessive viscosity in ophthalmic formulations?

    <p>Blurred vision</p> Signup and view all the answers

    What is the primary form of liquid ophthalmics?

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

    What is the function of tonicity modifiers in ophthalmic solutions?

    <p>To adjust osmolarity for stability</p> Signup and view all the answers

    How are most solution formulations sterilized?

    <p>Through heat or filtration</p> Signup and view all the answers

    What is the primary purpose of using finely micronized drug particles in suspensions?

    <p>To promote rapid dissolution</p> Signup and view all the answers

    Why can't suspensions be filter sterilized?

    <p>It would remove the drug particles from the formulation</p> Signup and view all the answers

    What roles do chelating agents, like EDTA sodium, serve in ophthalmic products?

    <p>Enhancing the activity of preservatives</p> Signup and view all the answers

    Which component is frequently added to ointments to reduce their viscosity?

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

    What is the disadvantage associated with the use of ointments in ophthalmic applications?

    <p>Prolonged blurred vision</p> Signup and view all the answers

    How do emulsions primarily differ from suspensions in terms of drug formulation?

    <p>Emulsions utilize surfactants for stabilization</p> Signup and view all the answers

    What is the primary advantage of using gelling agents like carbomers in ophthalmic gels?

    <p>They facilitate once-daily dosing</p> Signup and view all the answers

    What type of ophthalmic product is commonly packaged in dropper bottles?

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

    Which of the following is a common surfactant used in ophthalmic products?

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

    What is the primary use of suspensions in ophthalmology?

    <p>To allow for prolonged drug release</p> Signup and view all the answers

    Study Notes

    Ophthalmic Drug Delivery

    • The primary goal of ophthalmic drugs is local treatment, not systemic absorption. Absorption's significance depends on drug potency and strength.

    • Systemic absorption pathways include:

      • Nasolacrimal drainage: Drops drain through the nasal cavity.
      • Nasal structures: Absorption in the nasal cavity, nasopharynx, and lacrimal sac is possible, including absorption through mixing with saliva.
      • Gastrointestinal tract: Swallowed drugs are absorbed.
      • Conjunctival absorption: Rich blood supply allows for more permeable absorption.
      • Trabecular meshwork: Drainage through this meshwork allows drugs to enter the bloodstream.

    • Over 50% of ophthalmic drugs can be systemically absorbed. Drugs absorbed via the GI tract bypass the hepatic first-pass effect.

    Dosage Form Considerations

    • Sterility: Crucial for ophthalmic products, similar to injectable drugs. Contamination can lead to serious consequences, including blindness.
    • Pseudomonas aeruginosa is a significant corneal ulcer-causing organism.
    • Sterility testing is mandated for commercially manufactured ophthalmic medications.
    • Antimicrobial preservatives are necessary in multi-dose eye drops for sterility maintenance; single-use drops typically don't need these preservatives.

    Preservatives

    • Benzalkonium Chloride (BAK): Is the most commonly used preservative, effective against Pseudomonas aeruginosa, but can damage corneal epithelium at high concentrations.
    • Alternatives include polyquad (polyquaternium 1), which is less sensitizing, and thimerosal.
    • Oxidizing agents like sodium perborate are newer and act via oxidation of microbes.

    pH and Osmolarity

    • Ideal pH for ophthalmic products is around 6.6-7.8, matching tear film pH.
    • Buffers (acetate, phosphate, citrate, borate) help maintain product pH stability, solubility, and patient comfort.
    • Maintaining isotonicity (300mOsm/kg) like tears is crucial for patient comfort, although some products are intentionally hypertonic. (eg 5% NaCl)
    • Viscosity Modifiers: Viscosity affects residence time and drug diffusion; increased viscosity can cause blurred vision, while prolonged contact and reduced drainage are benefits. (eg glycerin, cellulose derivatives, polyvinyl alcohol, polyethylene glycols (PEGs))

    Ophthalmic Formulations

    • Solutions: Most common form, involving dissolving the drug and excipients, followed by sterilization (heat or 0.2 micron membrane filtration).
    • Suspensions: Finely micronized particles for minimized irritation and improved dissolution. Used for poorly soluble drugs or to enhance drug stability.
    • Emulsions: Less common, employ lipophilic drugs dissolved in oil phase and emulsifiers for stabilization.
    • Ointments/Gels: Prolonged contact time, commonly petrolatum-based ointments that can be sterilized. Gels use gelling agents like carbomers and cellulose derivatives to achieve extended contact.

    Administration

    • Wash hands, tilt head back, and pull down lower eyelid to create a pouch.
    • Instill one drop precisely into the conjunctival sac and keep eye closed for 30 seconds.
    • Avoid rubbing, wiping, or squeezing the eye. Replace the dropper tip cap without touching it.
    • Consider waiting at least five minutes between consecutive drops.

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    Related Documents

    Ophthalmic Drug Delivery Study Guide PDF

    Description

    Explore the essential aspects of ophthalmic drug delivery, focusing on local treatment methods and systemic absorption pathways. Understand key considerations for dosage forms, including sterility and potential absorption routes, to ensure effective and safe ocular therapies.

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