Ophthalmic Lecture Flashcards
What is a topical dosage form?
Instilled onto the external surface of the eye
What is a intraocular dosage form?
Administer by injection inside the eye
What is periocular dosage form?
Adjacent to the eye
What is intraocularly implanted mean?
Implanted as a ophthalmic device
What are drugs that are used in the eye?
Anti-glaucoma drugs Mydriatics & Cycloplegics Anti-inflammatory Anti-infectives Surgical adjuncts Diagnostic drugs Topical anesthetics Protectants & artificial tears
What is an example of anti-glaucoma drugs?
Pilocarpine HCl
What is an example of mydriatics & cycloplegics?
atropine
What is an example of anti-inflammatories?
Corticosteroids
What are the three types of anti-infectives and an example?
Antibiotics and antimicrobial agents (tobramycin)
Anti-fungal agents (amphotericin B)
Antiviral agents (ganciclovir)
What is an example of surgical adjuncts?
Irrigating solutions
What is an example of diagnostic drugs?
Sodium fluorescein
What is an example of topical anesthetics?
Tetracaine
What is an example of protectants & artificial tears?
Methylcellulose
What are three common opthalmic dosage forms?
Solutions (eyedrops)
Suspensions
Ointments
What are four new ophthalmic dosage forms?
Controlled Release devices
Ocular inserts
Gels, gel-forming solutions
Intravitreal injections and implants
What is the cornea?
Front clear, transparent tissue and is supplied with oxygen and other nutrients by lacrimal fluid
-Powerful refracting surface, allows light to enter the eye and provides much of the focusing power
What is the iris?
Part of the eye that gives it color
- Consists of muscular tissue that responds to surrounding light, making the pupil, or curricular opening in the center of the iris larger or smaller depending on brightness
What is the lens?
Transparent, biconvex structure, encased in a thin transparent covering
- Functions to refract and focus incoming light onto the retina
What is the retina?
Innermost layer in the eye
Coverts images into electrical impulses that are sent along the optic nerve to the brain where the images are interpreted
What effects drug availability?
Rapid solution drainage by gravity, induced lacrimation, blinking reflex and normal tear turnover
Low corneal permeability (acts as a lipid barrier
What is a typical drop volume, precorneal space of a healthy person and optimal volume administered? (in microliters)
20-50
7
5-10
How much applied drug is typically absorbed?
1-5%
Usually less than 3%
What is the retention time of ophthalmic solution on the eye surface?
Very short, 1-2 minutes
Fluids are rapidly removed from the eye by what?
Lacrimal drainage
Poor bioavailability leads to what/
Protective mechanisms (blinking, reflex lacrimation, nasolacrimal drainage) or anatomy of the eye (barrier properties of the cornea)
What is common to all ophthalmic dosages forms?
- Requires sterility of the finished product
- Appreciation for the sensitivity of ocular tissue to irritation and toxicity
- Inherent limitations in topical ocular absorption of most drugs
Define ophthalmic solutions
Sterile solutions, essentially free from foreign particles, suitably compounded and packaged for instillation into the eye
- Sterile
- Buffered
- Isotonic
- Non-irritating
- Non-greasy
- Efficacious
What are the most common means of administering a drug to the eye?
Solution
Xalatan Opthalmic solution (lantanoprost) is used for?
treatment of glaucoma