Dermatologicals Flashcards

1
Q

what are the 5 layers of the epidermis

A
stratum corneum 
stratum lucidum 
stratum granulosum 
stratum spinosum
stratum germinativum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the layers of the skin

A

epidermis
dermis
subcutaneous tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the pH of the epidermis

A

acidic (pH=5.5)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

role of the stratum corneum

A

major permeability barrier of the skin, controls percutaneous absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

role of the stratum lucidum

A

responsible for skin stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

role of the stratum granulosum

A

Site of biochemical activity (bioreactor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

role of the stratum spinosum

A

Change their morphology based on pressure placed on the skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

role of the stratum germinativum

A

□ Nucleated basal cells: dividing (mitosis) layer which replaces the shedding cells of stratum corneum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

where are the nerves and blood vessels of the skin located?

A

dermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the sink effect

A

Vascular supply: sink effect (dugs don’t accumulate in the skin–>the concentration gradient is always optimal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the function of the subcutaneous tissue

A
thermal barrier (Passive barrier doesn’t actually regulate heat: dermis blood vessels contract or expands based on heat)  
mechanical cushion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

functions of the skin

A

elasticity

protective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is an oleaginous base

A

○ Single phase–>ointments

Properties:
Hydrophobic 
Greasy 
Non-water washable 
occlusive 
emollient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does occlusion mean

A

formation of an impermeable layer on the skin to prevent evaporation of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does emollient mean

A

softens skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

advantages of oleaginous bases

A

Very stable vehicles
Non-irritating
Non-sensitizing
High compatibility with drugs (generally neutral)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

disadvantages of oleaginous bases

A

Greasiness
Stains clothing
Difficult to remove
Low patient acceptance (

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the liquids used to form oleaginous bases

A

fats and fixed oils Examples: almond, corn, cottonseed, olive, peanut, safflower, sesame seed, soybean oils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are semisolids used to form oleaginous bases

A

Petrolatum and white petrolatum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what solids are used to form oleaginous bases

A

waxes

paraffin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

do oleaginous bases need penetration enhancers

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how do permeation enhancers work

A

fluidization of the stratum corneum lipids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

do oleaginous bases require antimicrobials

A

No as they dont contain water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

do oleaginous bases need levigating agents

A

yes when incorporating a powder into the ointment
they are less than 5% of the formula
mineral oil
or the base can be used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

describe the process of fusion

A

melt the components together starting with the lowest melting point
then its is cooled with constant stirring until congealed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are absorption bases

A
Non-water washable bases 
Hydrophobic
Greasy 
Anhydrous; hydrophilic components provide water-absorbing properties
Upon water addition form w/o emulsions 
Occlusive 
Emollient 
Used in oozing conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

main components of absorption bases

A

Fats and fixed oils
Mineral oil
Petrolatum and white petrolatum
Waxes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

other excipients of absorptive bases

A

All have water-absorbing capacity
Upon addition of water, form w/o emulsions
ex: lanolin, hydrous lanolin, cetyl alcohol, stearyl alcohol, stearic acid, oleic acid, glycerol monostearate, cholesterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

do absorptive bases need an antioxidant

A

Yes

BHA, BHT, alpha-tocopherol

30
Q

do absorptive bases need penetration enhancers

A

determined on a case by case basis

31
Q

do absorptive bases need antimicrobials

A

NO

32
Q

use of levigating agents in absorptive bases

A

mineral oil
isopropyl myristate
glycerol, propylene glycol
absorption base can also be used

33
Q

what is an emulsifying base

A

Water washable bases
Anhydrous bases containing o/w emulsifying agents
Cream-like appearance
Miscible with water
Self-emulsifying
Upon addition of water form o/w emulsions
Emollient

34
Q

main components of emulsifying bases

A

Fats and fixed oils
Mineral oil
Petrolatum and white petrolatum
Waxes

35
Q

are emulsifying agents needed in emulsifying bases

A

Yes, mostly hydrophilic emulsifying agents (SURFACTANTS)

36
Q

are antimicrobials needed in emulsifying bases

A

NO

37
Q

are antioxidants needed for emulsifying bases

A

YES

BHA, BHT, alpha-tocopherol

38
Q

do penetration enhancers need to be used in emulsifying bases

A

on a case by case basis

39
Q

when a levigating agent needs to be used for incorporating a solid into an emulsion base what are the options

A
less than 5% of the formula 
mineral oil 
isopropyl myristate
glycerol, propylene glycol
emulsifying base can also b used
40
Q

for a dermatological emulsion what state is the oil phase

A

semi-solid

41
Q

what are the characteristics of a w/o dermatological emulsion

A

Greasier than o/w emulsions (because oil phase is external)
Emollient, cleansing action
Capable of absorbing oil-soluble compounds from the skin (make-up remover)

42
Q

what are the components of an w/o emulsion

A

Oil phase: all liquid, semisolid and solid excipients used for oleaginous bases: Fats and fixed oils, Mineral oil, Petrolatum and white petrolatum, Waxes
Emulsifying agents: Mostly surfactants
Water phase

43
Q

what are the characteristics of a o/w dermatological emulsion

A

Water washable
Soft
Non-occlusive
Moisturizing (increases water content–>restores hydration of the skin)
Penetration enhancement of the drug compounds

44
Q

are antioxidants used in emulsions?

A

Oil-soluble antioxidants: BHT,BHA, Alpha-tocopherol

Water-soluble: Ascorbic acid, Sodium bisulfate

45
Q

do penetration enhancers need to be used in emulsions

A

evaluated on a case by case basis

Isopropyl myristate, oleic acid, oleyl alcohol

46
Q

are preservatives required in emulsions

A

YES:essential
ex: alcohol, benzoic acid, phenols, methyl and propyl parabens

47
Q

are humectants required for emulsions

A

Yes

propylene glycol, glycerol, PEG

48
Q

is a levigating agent required to incorporate a solid into an emulsifying base

A

sometimes
use mineral oil, isopropyl myristate
can also use the water phase

49
Q

what is a paste

A

Oleaginous bases with 20% or more solids suspended in the base

50
Q

excipients of a paste

A
Hydrocarbon bases: all liquid, semisolid, and solid excipients used for oleaginous bases 
 Fats and fixed oils
Mineral oil 
 Petrolatum and white petrolatum 
Waxes
51
Q

is a paste water washable

A

NO, forms a thick impermeable layer on the skin as a protective action

52
Q

is the use of a levigating agent appropriate

A

NO

53
Q

what is a hydrophillic base

A

water washable base
Ointment like consistency (soften or melt on the skin)
Non-occlusive, mix with skin exudates
Doesn’t stain clothes (greaseless)
Non-irritant
Chemically stable: dont hydrolyze, deteriorate, don’t support mold growth
Cannot take up more than 8% water (loose consistency)

54
Q

what are some incompatibilities with hydrophilic bases

A

Reduce the antimicrobial activity of quaternary ammonium compounds and parabens
Inactivate bacitracin and penicillin

55
Q

what are the advantages of hydrophilic bases

A

Anhydrous–>useful for drugs that hydrolyze

Good patient compliance: non-staining, non-occlusive

56
Q

what are examples of hydrophilic bases

A

Mixtures of low and high molecular weight polyethylene glycols (PEG):
MW 200-700–>liquid
MW 1000–>semi solid
MW>1000–>increasingly solid (flaky)

57
Q

do hydrophillic bases require antioxidants

A

yes

water soluble antioxidants: ascorbic acid, sodium bisulfate

58
Q

do hydrophilic bases require penetration enhancers

A

can use propylene glycol

59
Q

do hydrophilic bases require humectants or preservatives

A

NO

60
Q

what are gels

A

Water washable bases
Liquid-rich two-component semi-solid colloidal systems
Natural or synthetic polymers form a 3D matrix throughout a hydrophilic liquid
Properties: Dissolves in water, Good for hairy areas, Water-soluble drugs are easily incorporated either dissolved in the aqueous phase or dispersed in gel

61
Q

do gels require antioxidants

A

ascorbic acid, sodium bisulfate

62
Q

do gels require penetration enhancers

A

case by case

propylene glycol can be used

63
Q

are preservatives required

A

can use the parabens

64
Q

are humectants required in gels

A

YES: prevents product from drying out
ex: propylene glycol, glycerol, PEG

65
Q

what is special about compounding gels

A

require time for hydration: sometimes takes up to 24 hours

66
Q

what is a newtonian system

A

Flow in which viscosity is a constant value: it doesn’t change with the force applied to it

67
Q

what is a non-newtonian system

A

Flow in which viscosity isnt a constant value–>viscosity changes with the force applied to it

68
Q

what is plastic flow

A

Materials will not flow if the shear stress is below a certain value (liquid flows quite readily once the yield value is exceeded)
Ex: flocculated suspensions, ointments, creams, ketchup

69
Q

what is pseudoplastic flow

A

Material shows decreasing viscosity with increasing shear rate=shear thinning
Solution at rest the interactions between molecules develops and chains become tangled
With stirring/shaking the interactions decrease and therefore viscosity

70
Q

what is dilantant flow

A

Viscosity increases with increasing shear rate=shear thickening
By increasing shear rate the particles become displaced from their even distribution–>clumps form–>increased resistance to flow–>material appears paste like

71
Q

what is thixotropy

A

Reversible time-dependent decrease in apparent viscosity–>gel-sol-gel
Viscosity is dependent on the length of time shear stress is applied
The structure of the liquid doesn’t reform immediately after altering its original flow properties