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DDS > 4.2-4.3 Ophthalmic (6) > Flashcards

4.2-4.3 Ophthalmic (6) Flashcards

1
Q

Ophthalmic products are designed for (systemic or local) use

A

local

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2
Q

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

A

glaucoma, infections, inflammation, dry eyes

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3
Q

Need for deep penetration don’t use topical product instead use injections such as ___+___ for faster, higher, and more deeply distributed ocular levels.

A

Subconjunctival and intraocular

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4
Q

The ___ concentric layer consist of the retina

A

innermost

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5
Q

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

A

Outermost

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6
Q

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

A

Middle

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7
Q

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

A

lens

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8
Q

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

A

iris

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9
Q

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 ____

A

Schlemm’s Canal

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10
Q

____ 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.

A

Conjunctiva (Conjunctival)

Drops instilled in “cul-de-sac”

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11
Q

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

A

Lacrimal

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12
Q

_____ the small openings to the lacrimal canaliculi.

A

Puncta

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13
Q

_____ 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.

A

Nasolacrimal apparatus

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14
Q

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

A

nasopharynx

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15
Q

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

A

blinking of an eye

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16
Q

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..

A

cornea

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17
Q

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.

A

anterior

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18
Q

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

A

posterior (need deep penetration)

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19
Q

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

A

cornea

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20
Q

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

A

Cornea

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21
Q

Tear film consists of three layers: …

A

Mucoid layer
tear fluid
lipid film

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22
Q

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

A

Mucoid layer

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23
Q

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

A

Tear fluid

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24
Q

_____ 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

A

Lipid film

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25
Q

The concentration of drug in the tear film provides the driving force for passive diffusion where passive diffusion dominates _____ permeation

A

corneal

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26
Q

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 —

A

stroma

other two layers are lipophilic

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27
Q

Corneal epithelium is a ____ epithelium, so drug must penetrate many layers

A

stratified squamous

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28
Q

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.

A

lipophilic

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29
Q

Stroma is mostly water so it is a (hydrophilic or lipophilic) barrier

A

hydrophilic (barrier to lipophilic drugs)

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30
Q

____ layer of cornea is a single cell layer that provides metabolic exchange between cornea and aqueous humor, and most permeable lipophilic barrier.

A

Endothelium

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31
Q

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

A

Octanol/water partition coefficient

32
Q

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

A

faster

33
Q

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

A

greater

34
Q

Takes ____ mins for peak concentration of aqueous humor.

A

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

35
Q

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

A

5

36
Q

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

A

30 microliters

37
Q

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

A

increases

38
Q

Blinking leads to a residual volume of ___ microliters

A

10

39
Q

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

A

gravity, blinking

40
Q

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

A

aqueous

41
Q

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

A

posterior

42
Q

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)

A

melanin

43
Q

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

A

aqueous

44
Q

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

A

nasal

45
Q

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

A

greater

conjunctiva is highly vascularized

46
Q

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

A

50

47
Q

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

A

Pseudomonas aeruginosa

48
Q

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.

A

Benzalkonium Chloride (BAC)

49
Q

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

A

Polyquad

50
Q

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

A

Thimerosal

51
Q

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

A

Oxidants

52
Q

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).

A

6.6, 9

53
Q

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

A

tear film

54
Q

____ 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).

A

Isotonicity

55
Q

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

A

Hypertonic

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

56
Q

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

A

NaCl, Mannitol, Dextrose

57
Q

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

A

Increased (which increase bioavailability)

58
Q

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

A

high

59
Q

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

A

glycerin, cellulose derivatives, polyvinyl alcohol, PEGs, Carbomer

60
Q

____ is an appropriate way to sterilize solution liquid ophthalmic.

A

Membrane filtration

61
Q

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

A

10

to reduce irritation, and speed up dissolution

62
Q

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

A

suspensions

63
Q

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

A

suspension

64
Q

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.

A

longer

65
Q

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

A

emulsions

66
Q

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

A

Surfactant emulsifier

67
Q

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

A

BAC (benzalkonium chloride)

68
Q

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

A

Ointment

69
Q

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.

A

Mineral Oil

70
Q

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.

A

gel

71
Q

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).

A

30

72
Q

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

A

5 minutes

73
Q

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

A

fast, long

74
Q

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

A

10 minutes

75
Q

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

A

BAC

76
Q

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

A

30

DDS (29 decks)

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