4.2-4.3 Ophthalmic (6) Flashcards
Ophthalmic products are designed for (systemic or local) use
local
Topical ophthalmic products are used to treat ocular conditions such as …
glaucoma, infections, inflammation, dry eyes
Need for deep penetration don’t use topical product instead use injections such as ___+___ for faster, higher, and more deeply distributed ocular levels.
Subconjunctival and intraocular
The ___ concentric layer consist of the retina
innermost
The -____ concentric layer consists of conjuctiva/sclera and the cornea. The layer we see.
Outermost
The ____ concentric layer consist of uveal tract (choroid, ciliary body, and iris)
Middle
The inside is divided by the ____ into aqueous (anterior segments) and vitreous (posterior segment) humors.
lens
The aqueous humor is divided by the ___ into anterior and posterior chambers
iris
Aqueous humor is continuously generated by ciliary bodies and flows from the posterior chamber through the pupil, and exits to the systemic circulation through the ____
Schlemm’s Canal
____ is a thin, transparent, vascularize mucous membrane that extends from the edge of cornea, across portion of sclera, then extends to internal surface of eyelids to form ____ sacs.
Conjunctiva (Conjunctival)
Drops instilled in “cul-de-sac”
_____ gland is responsible for tear production, the tears function is the removal of foreing material through the puncta.
Lacrimal
_____ the small openings to the lacrimal canaliculi.
Puncta
_____ is the drainage system for lacrimal fluid (tears); tears drain through the canaliculi to the lacrimal sac then to the nasal cavity via the lacrimal duct.
Nasolacrimal apparatus
Tear drainage from the nasal cavity they are moved towards the —-
nasopharynx
Tear drainage occurs by gravity and through an active process employing a pumping mechanism is the action of…
blinking of an eye
Drug target areas include pre-ocular structures (conjunctiva + eyelid), Cornea, and tissues in the posterior and anterior segment. The target area with main nerve endings is..
cornea
Majority of drug targets are through the ____ segment where drug must penetrate through the cornea to get there and this segment contain receptors responsible site for glaucoma.
anterior
Not likely to be a target for topical products is the ____ segment
posterior (need deep penetration)
The major pathways for topical ophthalmic to reach intraocular tissues are through the sclera and dominantly the -____
cornea
____ is a complex, optically transparent tissue covered by a tear film.
Cornea
Tear film consists of three layers: …
Mucoid layer
tear fluid
lipid film
____ layer in the tear film is responsible for keeping the corea wettable (wet) and involved in adhesion of aqueous tear fluid.
Mucoid layer
_____ a layer in the tear film that is an aqueous solution in inorganic electrolytes, proteins (enzymes+ immunoglobulins), and glucose
Tear fluid
_____ layer in the tear film is a layer of wax and cholesterol esters absorbed to the tear fluid where it is responsible for the reduction of evaporation of tear fluid
Lipid film
The concentration of drug in the tear film provides the driving force for passive diffusion where passive diffusion dominates _____ permeation
corneal
Most important layers for drug absorption in the cornea – outer to inner– are the epithelium, stroma, and endothelium. The layer that is hydrophilic is/are the —
stroma
other two layers are lipophilic
Corneal epithelium is a ____ epithelium, so drug must penetrate many layers
stratified squamous
The squamous cells on the surface (cornea) are surrounded by tight junctions and have microvilli. It is a (lipophilic or hydrophilic) barrier and non-ionized drug permeates better.
lipophilic
Stroma is mostly water so it is a (hydrophilic or lipophilic) barrier
hydrophilic (barrier to lipophilic drugs)
____ layer of cornea is a single cell layer that provides metabolic exchange between cornea and aqueous humor, and most permeable lipophilic barrier.
Endothelium