4.2-4.3 Ophthalmic (6) Flashcards by Crystal Naranjo

Ophthalmic products are designed for (systemic or local) use

local

How well did you know this?

Not at all

Perfectly

Topical ophthalmic products are used to treat ocular conditions such as …

glaucoma, infections, inflammation, dry eyes

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

The ___ concentric layer consist of the retina

innermost

How well did you know this?

Not at all

Perfectly

The -____ concentric layer consists of conjuctiva/sclera and the cornea. The layer we see.

Outermost

How well did you know this?

Not at all

Perfectly

The ____ concentric layer consist of uveal tract (choroid, ciliary body, and iris)

Middle

How well did you know this?

Not at all

Perfectly

The inside is divided by the ____ into aqueous (anterior segments) and vitreous (posterior segment) humors.

lens

How well did you know this?

Not at all

Perfectly

The aqueous humor is divided by the ___ into anterior and posterior chambers

iris

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

____ 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”

How well did you know this?

Not at all

Perfectly

_____ gland is responsible for tear production, the tears function is the removal of foreing material through the puncta.

Lacrimal

How well did you know this?

Not at all

Perfectly

_____ the small openings to the lacrimal canaliculi.

Puncta

How well did you know this?

Not at all

Perfectly

_____ 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

How well did you know this?

Not at all

Perfectly

Tear drainage from the nasal cavity they are moved towards the —-

nasopharynx

How well did you know this?

Not at all

Perfectly

Tear drainage occurs by gravity and through an active process employing a pumping mechanism is the action of…

blinking of an eye

How well did you know this?

Not at all

Perfectly

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

How well did you know this?

Not at all

Perfectly

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.

How well did you know this?

Not at all

Perfectly

Not likely to be a target for topical products is the ____ segment

posterior (need deep penetration)

How well did you know this?

Not at all

Perfectly

The major pathways for topical ophthalmic to reach intraocular tissues are through the sclera and dominantly the -____

cornea

How well did you know this?

Not at all

Perfectly

____ is a complex, optically transparent tissue covered by a tear film.

Cornea

How well did you know this?

Not at all

Perfectly

Tear film consists of three layers: …

Mucoid layer
tear fluid
lipid film

How well did you know this?

Not at all

Perfectly

____ layer in the tear film is responsible for keeping the corea wettable (wet) and involved in adhesion of aqueous tear fluid.

Mucoid layer

How well did you know this?

Not at all

Perfectly

_____ a layer in the tear film that is an aqueous solution in inorganic electrolytes, proteins (enzymes+ immunoglobulins), and glucose

Tear fluid

How well did you know this?

Not at all

Perfectly

_____ 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

How well did you know this?

Not at all

Perfectly

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

Drugs with a moderate ____- at physiological pH are best absorbed because of the diverse barriers.

Octanol/water partition coefficient

The greater the concentration in the tear film, the (slower or faster) the penetration

faster

There will be (greater or lesser) absorption that occurs through a damage epithelium.

greater

Takes ____ mins for peak concentration of aqueous humor.

20-60 mins *****not sure if its important ******

Normally, less than ___% of the dose (instilled as drops) will cross the cornea

The volume that can be momentarily accomodated in the lower cul-de-sac without spillage is ___ or less.

30 microliters

Blinking (increases or decreases) the spillage and facilitates removal by the nasolacrimal apparatus.

increases

Blinking leads to a residual volume of ___ microliters

____+___ forces fluid through puncta-> nasolacrimal apparatus--> nasal cavity

gravity, blinking

Greatest concentrations are usually achieved within the ___ humor in the anterior region of the eye

aqueous

The amount of product/drug reaching the ____ region is usually insignificant and not achievable through topical product

posterior

Some lipophilic drugs can bind to ____ in the iris in the dark irides (brown eyes) and can slow or reduce drug effect or act as depot (slow release of drug)

melanin

Elimination to the systemic circulation via ____ humor turnover and/or through uveal blood vessels.

aqueous

A significant fraction of drug can be systemically absorbed in the ___ cavity

nasal

The absorption through blood vessels in the conjunctiva -- conjunctiva is more permeable than cornea and covers a (lesser or greater) surface area-- higher permeability=drug absorption

greater | conjunctiva is highly vascularized

Overall impact of systemic absorption is that over ___% of instilled dose can potentially be systemically absorbed

____ is of great concern as it can invade damaged cornea and cause corneal ulceration and blindness. Sterility required for ophthalmic products.

Pseudomonas aeruginosa

Most common ophthalmic preservative is ____ it is widely used as it is effective against P. Aeruginosa. This excipient has surfactant properties and can damage corneal epithelium if concentrated too high and affect corneal penetration.

Benzalkonium Chloride (BAC)

Alternative preservative excipient to BAC is ____ where is it less damaging and it does not penetrate the cornea well and almost nonsensitizing.

Polyquad

Preservative excipient ____ is an organic mercurial and is not widely used because hypersensitivity is a problem.

Thimerosal

Preservative excipient ____ such as sodium perborate, stabilized oxcychloro complex brand name= Purite

Oxidants

Solutions below pH of ___ and above pH of ___ have been associated with irritation, reflex tears, and blinking which speeds up elimination of drug from the eye (drug loss).

6.6, 9

The _____ has very limited buffer capacity (due to low fluid volume) = so instilled fluid will control pH for several minutes.

tear film

____ is very important for comfort- instilled fluids fat outside of the normal range can irritate, leading to reflex tearing and blinking (leading to drug loss).

Isotonicity

Ideally eye product should be isotonic to prevent irritation. However, some products are intentionally (hyper or hypo) -tonic such as to reduce edema in the cornea

Hypertonic | e.g. 5% NaCl solution to treat corneal edema

Excipient: Tonicity modifiers that increase tonicity or osmolarity are ____, buffers also contribute to tonicity.

NaCl, Mannitol, Dextrose

(increased or decreased) viscosity can increase retention time/ reduce drainage rate.

Increased (which increase bioavailability)

Viscosity that is too (high or low) can be irritating and cause blurring and increase crusting.

high

Excipients: Viscosity modifiers would be ____, agents have lubricating effect as well (artificial tear) and potential problems would be crust formation and transient blurring

glycerin, cellulose derivatives, polyvinyl alcohol, PEGs, Carbomer

____ is an appropriate way to sterilize solution liquid ophthalmic.

Membrane filtration

For suspension ophthalmic products the particle size should be reduced to less than ____ micrometers.

10 | to reduce irritation, and speed up dissolution

Cannot filter-sterilize _____ since the drug particles will be removed .

suspensions

Ophthalmic (solution or suspension) is best used if the drug is poorly water-soluble or to improve drug stability

suspension

Ophthalmic suspension do not provide a drug depot thus they will remain in the cul-de-sac for (shorter or longer) period of time and not penetrate through the puncta.

longer

Ophthalmic ____ is most uncommon and alternative for lipophilic drugs, drug is dissolved in oil, and surfactant emulsifiers used to form and stability the product

emulsions

Drug dissolved in oil, _______ usually used to form and stabilize the emulsion.

Surfactant emulsifier

Important function of EDTA (chelator) is to work synergistically with _____ to fight against P. aeruginosa.

BAC (benzalkonium chloride)

Semisolid Ophthalmic such as ____ prolong contact time (0.5% per minute cleared) however can blur vision and cause matting of eyelid.

Ointment

The ointment base is usually white petrolatum, with or without ______, ____ reduces the viscosity of the Vaseline to make it easier for product to come out of the tube.

Mineral Oil

Semisolid Ophthalmic such as ____, is least commonly used and can prolong contact time. The high viscosity slows removal from eye surface and good at releasing the drug. Liberation is fast compared to other dosage forms.

gel

Proper usage of eye drop include the last step where with the eye closed, apply gentle pressure against the inner corner of eye for at least ____ secs (nasolacrimal occlusion) to slow drainage and avoid blinking (excessively).

Wait at least ____ minutes before applying second drop or else the second drop will wash out the first one.

5 minutes

Apply the (fast/slow) acting drops at least 5 minutes before (long/short) acting drops.

fast, long

Eye drops should be applied before eye ointment since the oint. film will be a barrier. Apply at least __ minutes before eye ointment.

10 minutes

Do not instill eye drops while wearing contacts because some ingredients such as ____ can bind to the contacts.

BAC

Once you open your eye drops, the product should be discarded in ___ days.