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Compounding Final > Ophthalmic and Nasal part 1 (7 concept 2 calcs) > Flashcards

Ophthalmic and Nasal part 1 (7 concept 2 calcs) Flashcards

1
Q

*particle size limit for ophthalmic suspensions

A

10 micrometers

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2
Q

*can ophthalmic suspensions be sterilized using filtration?

A

NO

pore size is 0.22 micrometers. the particles cant pass - too large

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3
Q

**name the 5 layers of the cornea from top to bottom and state whether lipophilic or hydrophilic

A

top - epithelium (lipophilic)
bowman’s membrane (too thin)
stroma (hydrophilic)
descemet’s membrane (too thin)
endothelium (lipophilic)

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4
Q

**hydrophilic drug is to be administered through the eye.

what layer serves as the “barrer” and is thus the rate limiting step?

what about for a lipophilic drug?

A

crossing the EPITHELIUM

for a lipophilic drug, the STROMA is the barrier and rate limiting step

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5
Q

what is the main pathway for permeation of drugs into intraocular tissues?

*what is it covered by?

A

the cornea

covered by a tear film

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6
Q

*function of the tear film

A

covers the cornea and keeps it MOIST – provides lubrication

protects against infection, removes debris, and provides nutrients

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7
Q

*what structure provides lubrication for the movement of the eyelids

A

the tear film

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8
Q

*____ is involved in the adhesion of the aqueous phase to the cornea (wetting)

A

MUCIN

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9
Q

***normal volume of tear fluid with blinking

A

7-10 micrometers

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10
Q

*approximate pH of the tear fluid and osmolality

A

pH 7-8

300mOsmol/L

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11
Q

the very top of the tear film has a ___ layer

A

LIPID layer - to protect the underlying aqueous layer

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12
Q

which 2 components help to expel mucin into the tear film

A

the mucoid layer and microvilli

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13
Q

**true or false

the conjunctiva is made up of connective tissue and is highly vascularized

A

FALSE - epithelial tissue and is highly vascularized - lot of blood vessels

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14
Q

white part of the eye is called the….

A

sclera

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15
Q

what is the sclera made of and what is its function

A

tough, fibrous tissue

covers the posterior segment of the eye - protects from physical damage

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16
Q

*does the conjunctiva help to lubricate the eye?

A

YES - produces mucus and tears - also protects against microbes

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17
Q

**under normal conditions, what is the tear volume in the conjunctival sac

A

7-10 microliters

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18
Q
  • maximum volume the conjunctival sac can hold
A

30 microliters

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19
Q

*commercial eye droppers typically deliver…..

A

25-50 microliters (avg 39) – more than the conjunctival sac can hold!

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20
Q

as mentioned, commercial eye drops typically deliver MORE than what the conjunctival sac can even hold

what happens because of this?

A

rapid reflex blinking and tear secretion

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21
Q

most of the instilled drug from an eye drop leaves though _____ and the excess is spilled where?

A

the lacrimal drainage system

excess spilled onto cheeks

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22
Q

*for how long does the drug reside in the conjunctival sac

A

3-5 mins (then will drain)

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23
Q

**what are the 2 pathways to get into ocular tissue

A

-corneal penetration

-conjunctiva-sclera pathway (non-corneal route)

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24
Q

*which drugs typically go through the corneal route and which typically go through the conjunctiva-sclera route

A

cornea – small, low MW, lipophilic drugs

conjunctiva-sclera - hydrophilic, high MW drugs

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25
Q

which structure is usually the site of drug action?

for which of the 2 pathways does the drug usually get there?

A

aqueous humor

corneal route

conjunctiva-sclera usually goes to systemic circulation and does not get to the aqueous humor

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26
Q

when a drug is administered via eye drop, explain the distribution between the corneal penetration and the conjunctiva-scleral route

A

less than 5% of the dose goes through ocular absorption (corneal) LOSSES ARE SIGNIFICANT

50-100% gets systemically absorbed through the conjunctiva-scleral route

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27
Q

*true or false

the non-corneal route of absorption is usually NOT productive, due to removal by the blood circulation

A

TRUE

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28
Q

true or false

it is an ABSOLUTE REQUIREMENT for ophthalmic solutions to have sterility and clarity

A

TRUE

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29
Q

*4 different kinds of inactive ingredients that are added to ophthalmic solutions

A

preservatives (if multi dose)
antioxidants
wetting agents
viscosity agents

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30
Q

*anything with “sulfite” what kind of inactive ingredient is it

A

antioxidant

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31
Q

*what is chlorobutanol

A

preservative

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32
Q

*what are polysorbate 80 and polysorbate 20 and why are they added to ophthalmic solutions?

A

wetting agents

added to decrease interfacial tension between the eyes and the product

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33
Q

*“polyinyl”

A

viscosity agent
PVA

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34
Q
  • cellulose derivatives
A

viscosity agents - stay longer on the eyes

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35
Q

pH range for ophtalmic solutions

A

6.5-8.5

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36
Q

**what size filter is used to sterilize eye drops

A

0.22 micrometers

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37
Q

eye drops are relatively easy to prepare, filter, and sterilize

what is the major problem with eye drops?
what can be done to help solve this issue?

A

short retention time on the eye - they’re very runny

can add polyvinyl polymers and cellulose derivatives, or just close the eyes after applying the drops — this will prolong contact time and LIMIT systemic exposure

38
Q

poorly water soluble drugs for ophthalmic drug delivery are formulated as….

A

suspension

39
Q

true or false

ophthalmic suspensions have a longer duration of action than solutions

A

TRUE

bc particles retained in the conjunctiva

however – large particle size also means more irritation – so may be removed faster (LIMIT TO 10 MICROMETERS**)

40
Q

why are ophthalmic ointments not very popular

A

greasiness and blurred vision

41
Q

ophthalmic ointments are recommended to be administered at what time?

A

nighttime

42
Q

***rank drug residence time of eye products

suspensions
ointments
solutions

A

shortest - solution
suspension
longest - ointment

43
Q

name a drug that is more effective as an eye ointment rather than solutions

A

antibiotics like tetracycline

44
Q

true or false

gels have a longer residence time than solutions

A

true

45
Q

ophthalmic gels are formulated as in situ gels

what does this mean

A

liquid in their container, but in contact with hotter temp or to neutral-alkaline pH, they well become gels

46
Q

example of a temp-sensitive eye gel and a pH-sensitive eye gel

A

temp sensitive - Pluronic F-127

pH-sensitive - Carbopol 940

47
Q

explain what eye inserts are

A

very slow drug release and long residence time to minimize systemic absorption and side effects

either placed on the cornea or the lacrimal cul de sac

48
Q

if patient has more than 1 drug to put in via eye drop, how long should they wait between each?

A

5 mins (remember - residence time is 3-5 mins)

dont want to wash out the first

49
Q

how can a patient limit the amount of eye drop that goes into systemic circulation?

(via conjunctiva-scleral route)

A

pressing on the tear duct while putting in the drop and for a few minutes aftter

50
Q

*in general, around ____% of ophthalmic formulations can be absorbed into the ocular tissues

A

less than 5%

51
Q

do drugs delivered via nasal drug delivery need to be sterile

A

no

52
Q

**absorption properties through the nasal cavity

(ie - fast or no?)

A

rapid absorption and fast onset

this is bc the nasal epithelium has rick vascularization

53
Q

*true or false

an advantage of nasal preparations is that they avoid first pass metabolism, and are also able to be self administered

A

true

54
Q

**a disadvantage of nasal delivery is that they are limited to what kind of drug?

A

only potent drugs

25-200 microliters ONLY is allowed

also, MW cutoff is 1000 kDaltons – because larger than that wont be absorbed

55
Q

**relative drug residence time for nasal preparations and WHY

A

SHORT

because of the mucociliary clearance of drugs – thus need FREQUENT administration

56
Q

**true or false

a disadvantage of nasal preparations is that they need to be administered frequently

A

TRUE - bc of short residence time due to mucociliary clearance

57
Q

*true or false

a disadvantage of nasal preparations is that adverse reactions are common

A

TRUE – bc the cilia are very fragile

58
Q

*a disadvantage of nasal delivery is that pathophysiologic conditions affect the drug permeation/absorption through the nasal mucosa

why?

A

ie - past drug use (cocaine) may increase absorption

also bloody nose and nasal congestion may affect

59
Q

**enzymatic activity of the nasal mucosa and is this an advantage or diadvantage

A

LOWER than the GI tract - advantage

(but still does have oxidative enzymes)

60
Q

***major structure for absorption for nasal delivery

A

turbinate!

has a large surface area and good blood supply

61
Q

**what structure allows for drug delivery to the BRAIN through the nasal route

A

the olfactory region

62
Q

can we deliver proteins and peptides through nasal route?

A

YES - less enzymatic activity than GI tract

63
Q

explain what the mucociliary clearance is

A

body’s defense mechanism - the reason that the residence time for nasal delivery is so short

cilia beat at 1000 strokes/min to propel the mucus toward the nasopharynx

64
Q

**true or false

when formulating a nasal drug delivery, the medication must be POTENT AND be greater than 1000 daltons

A

FALSE
potent and LESS THAN 1000 daltons

65
Q

**when formulating nasal drugs, what should the hydro/lipophilicty be

A

balanced

bc lipophilicity gives permeability and hydrophilicity allows drug to be carried in the mucus (mainly contains water)

66
Q

***when formulating nasal drugs, should they be:

hypertonic
isotonic
hypotonic

A

isotonic OR hypotonic –

bc hypotonic means that there is more water in the product that the nasal environment, so water will rush out of drug and the drug will thus become viscous and stay in the nasal cavity longer

67
Q

***optimal size of aerosol droplets for nasal delivery

A

5-7 micrometers

68
Q

**if aerosol droplets for nasal formulations are smaller than ____, they will be ____

A

smaller than 0.5 micrometers, they will be exhaled

69
Q

___ and ___ are not commonly used as nasal formulations bc of irritation

A

ointments and powders

70
Q

*to improve nasal formulations, do we want to increase or decrease the viscosity

(and how do we do this)

A

INCREASE

can add PEG or glycerin

71
Q

**true or false

muco-adhesives should not be included in nasal formulations

A

FALSE - they should be added to decrease the MCC and prolong residence time

*****HOWEVER – issue because can increase the risk of microbial contamination – USE PRESERVATIVE!! LIKE BENZALKONIUM CHLORIDE

72
Q

**name 4 things that can be added as mucoadhesives in nasal formulations to improve residence time

A

alginates
xanthan gum
HPC
chitosan

73
Q

*to enhance absorption of nasal formulations, ____ may be added

however, what is an issue with this

A

surfactants

however, may disrupt the nasal epithelium and cause nasal irritation

74
Q

*incorporating ___ into nasal formulations can increase the drug solubility in nasal fluids

A

cosolvents

75
Q

*what is benzalkonium chloride

A

preservative

76
Q

*what is potassium sorbate

A

an antioxidant

77
Q

*what is alcohol

A

a cosolvent

78
Q

*what is polysorbate

A

a surfactant - enhances absorption

79
Q

*what is propylene glycol

A

a cosolvent

80
Q

*what is CMC

A

a mucoadhesive – increases viscosity

81
Q

*issue with mucoadhesives like gums and cellulose

A

increase the chance of microbial contamination — use preservative

82
Q

simplest and most convenient nasal formulation

A

nasal drops

83
Q

issue with nasal drops

A

cant deliver exact amount of drug

84
Q

for nasal sprays, what is the ideal ranfe of particles or droplets in order to be deposited in the nasal passages

A

5-7 micrometers

85
Q

**patient counseling on nasal spray for migraine

A

keep head UPRIGHT and close mouth

do NOT tilt head and do NOT lay down while delivering the dose

86
Q

*true or false

rapid drug absorption is expected for nasal delivery because of the RICH VASCULARIZATION IN THE TURBINATE

A

TRUE

87
Q

*true or false

nasal delivery does not avoid first pass effects

A

false - it does

88
Q

*MW cutoff for drug absorption via nasal route

A

1 thousand daltons

89
Q

*true or false

nasal mucosa has higher enzymatic activity than the GI tract

A

FALSE - lower

90
Q

**true or false

via nasal delivery, pathophysiological condition changes account for low reproducibility of absorption and action

A

TRUE

ie - mucus, blood, destroyed area, not inhaling completely, etc

issue with nasal delivery is LOW REPRODUCIBILITY

91
Q

can intranasal deliver drugs to the brain

A

yes - through the olfactory region

92
Q
A

Compounding Final (6 decks)

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