Test 1- Semisolid dosage forms 1 Flashcards

1
Q

What is the outermost layer of the skin?

A

Epidermis

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2
Q

What cells are actively dividing in the epidermis?

A

keratinocytes
Accumulate at the skin surface to form keratinized horny layer of skin (stratum corneum

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3
Q

What is the stratum corneum composed up?

A

Keratins
Lipids

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4
Q

What links the 15-25 layers of the stratum corneum?

A

Intercellular bridges

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5
Q

What does the intercellular space of the stratum corneum comprise of?

A

Lipophilic matrices alternating with hydrophilic layers

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6
Q

What covers the stratum corneum?

A

An acidic film made up of emulsified lipids

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7
Q

What does the skin do for the body?

A

Protect
regulate heat and water loss from the body

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8
Q

The stratum corneum is _____ meaning it swells to 3 or 5 times its original thickness when absorbing water

A

Hygroscopic

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9
Q

What are the 4 general effects of drugs applied to the skin?

A

An effect on the skin surface
An effect within the stratum corneum
A more deep seated effect requiring penetration into the epidermis and dermis
A systemic effect by delivery to the vasculature

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10
Q

What are the skin surface effects?

A

Protective agent (forming film) (deminishing loss)
An action against surface microrganism (anti infectives agent)
A cleansing effect (soap)

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11
Q

What drug effects can happen on the stratum corneum?

A

Increased moisture of the skin and resulting softening of the skin

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12
Q

What agents increase skin moisturization?

A

Occlusive agents

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13
Q

How does skin become moistened?

A

Hydration of dry outer cells (surface films)
Integration of water in the lipid rich intercellular laminae

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14
Q

What agent should be used for someone with psoriasis?

A

Keratolytic agents

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15
Q

What do keratolytic agents do?

A

Act to cause a breakup or sloughing of stratum corneum cell aggregates

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16
Q

How does the stratum corneum serve as a reservoir?

A

Topically applied drugs accumulate due to partitioning into or binding with skin components

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17
Q

What can the reservoir effect do?

A

Limit the migration of the drug away from the stratum corneum unless the capacity of the corneum is exceeded by providing excessive drug

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18
Q

What are some examples of drugs that exhibit significant skin interaction?

A

Corticosteroids, extrogens, benzocain, and scoplamine

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19
Q

What is p-aminobenzoic acid?

A

Sun screening agent that both penetrates and is substantive to stratum corneum cells

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20
Q

In psoriasis vulgaries, _____ play an important role since they are responsible for hyperkeratotic lesions

A

keratinocytes

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21
Q

What is a principal driving force for diffusion across the skin?

A

Thermodynamic activity of the permeant in the donor vehicle

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22
Q

What routes for permeation are important through skin?

A

Transcellular and intercellular

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23
Q

What are the physiochemical properties affecting drug permeation through the skin

A

Low molecular weight
Increased but balanced log P value
Solubility

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24
Q

How can a formulation alter the properties of the skin?

A

Enhance or retard permeation of a drug by increasing or decreasing its diffusivity and or solubilitywithin the stratum corneum

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25
Q

What is percutaneous absorption influenced by?

A

Physical and chemical properties of the active ingredient
Concentration
Vehicle
Variations in type of skin

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26
Q

When does cutaneous penetration of an active ingredient become enhanced?

A

Low molecular weight
Lipid soluble
Nonpolar

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27
Q

What are semisolid dosage forms intended for?

A

Topical application

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28
Q

When medicated what kind of effects do semisolid dosage forms give?

A

Local and systemic effects

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29
Q

When un medicated, what are semisolds used for?

A

Their physical effects as protectants or lubricants

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30
Q

What does occlusion usually mean?

A

The skin is covered directly or indirectly by impermeable films or substances. (these usually contain fats or polymer oils)

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31
Q

TF: Occlusion increases permeability and decreases the mean residence time

A

true

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32
Q

What are ointments?

A

Semisolid preparations intended for external application to the skin or mucous membranes

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33
Q

What are ointment bases?

A

Vehicles or diluents for drugs designed to facilitate drug transfer into the skin

34
Q

What are the 4 groups of ointment bases?

A

Oleaginous bases
Absorption bases
Water removable bases
Water soluble bases

35
Q

What effect does oleaginous/hydrocarbon bases have?

A

Have emollient/smoothing effect
Skin softening and moisturization effect

36
Q

How do oleaginous bases give a moisture effect?

A

Act as humectants by preventing moisture from escaping
Effective as occlusive dressing
Remain on skin for a long time without drying out

37
Q

Why are oleaginous ointments difficult to wash off?

A

They are immiscible with water

38
Q

What are levigating agents?

A

Mineral oil for oleaginous bases and glycerin for aqueous baes
Used to incorporate powdered substances into hydrocarbon bases

39
Q

What are some examples of hydrocarbon ointment bases?

A

Petrolatum
Yellow ointment
White petrolatum
White ointment

40
Q

What is petrolatum?

A

Purified mixture of semisolid hydrocarbons obtained from petroleum

41
Q

What are other names of petrolatum?

A

Yellow petrolatum or petroleum jelly

42
Q

hat is a commercial product of petrolatum?

A

Vaseline

43
Q

What is the color variation of petrolatum?

A

Yellowish to light amber

44
Q

What is another name for white petrolatum?

A

White petroleum jelly

45
Q

What is a commercial product of white petrolatum?

A

White vaseline

46
Q

What color is white petrolatum?

A

It doesnt have one it is completely decolorized petroleum

47
Q

What is the purpose of Petrolatum?

A

Used as an ointment base

48
Q

What is another name for yellow and white ointment?

A

Simple ointment

49
Q

What is simple ointment?

A

Purified wax of the honeycomb bee (bleached if white)

50
Q

What are the parts of simple ointment?

A

5 parts yellow or white wax
95 parts petrolatum

51
Q

What is the purpose of simple ointment compared to petrolatum?

A

It has a slightly greater viscosity than plain petrolatum

52
Q

What are the two types of absorption bases?

A

Those oleaginous bases that contain water in oil emulsifying agent, permitting aqueous solution incorporations

Those that are water in oil emulsion naturally permitting incorporation of additional quantities aqueous solution

53
Q

What are absorption bases used for?

A

Emollients/soothing agents

54
Q

Absorption bases do not provide _____

A

Occlusion

55
Q

Absorption bases absorb water up to ____ times their weight to incorporate a ____ soluble drug

A

2-3
water

56
Q

Why are absorption bases used as pharmaceutical adjuncts?

A

To incorporate small volumes of aqueous solutions into hydrocarbon bases (nonpolar)

First incorporate it into absorption base then into hydrocarbon base

57
Q

What are the contents of hydrophilic petrolatum

A

Cholesterol
Stearul alcohol
White wax
White petroleum

58
Q

What is lanolin obtained from?

A

Wool of sheep

59
Q

What is lanolin?

A

A purified wax-like substance, deodorized and decolorized

60
Q

Lanolin contains no more than ____% water?

A

0.25

61
Q

How is additional water incorporated into lanolin?

A

Mixing

62
Q

What is modified lanolin?

A

Processed to reduce free lanolin alcohols and any detergent and pesticide residues

63
Q

What are water-removable bases?

A

Oil in water emulsion

64
Q

What is another name for water-removable bases?

A

Water washable ointment bases
Easily washed

65
Q

What is the external phase of the water removable base emulsion?

A

aqueous

66
Q

What can water-removable bases be diluted with?

A

Water or aqueous solution

67
Q

What does hydrophilic ointment contain?

A

It is a water removable ointment base that has stearyl alcohol and white petrolatum
Purified water
Sodium lauryl sulfate
Propylene glycol, methyl paraben propylparaben

68
Q

What phase is purfied water in hydrophilic ointment?

A

Aqueous

69
Q

What phase is stearyl alcohol and white petrolatum in hydrophilic ointment?

A

Oleaginous phase

70
Q

What is sodium lauryl sulfate in hydrophilic ointment?

A

Emulsifying agent

71
Q

What is propylene glycol and parabens in hydrophilic ointment?

A

Antimicrobial preservative

72
Q

What do water soluble bases NOT contain?

A

Oleaginous components

73
Q

Water soluble bases are _____ water washable

A

Completely

74
Q

Why are water soluble bases completely water washable?

A

Because they soften greatly with the additionof water

75
Q

What are water soluble bases used for?

A

The incorporation of solid substances

76
Q

What is PEG?

A

Polyethylene glycol ointment
A polymer of ethylene oxide and water

77
Q

What do PEGs with molecular weight below 600 look like?

A

Clear colorless liquids

78
Q

What do PEGs with molecular weight above 1000 look like?

A

Wax like white material

79
Q

What do PEGs between 600-1000 MW look like?

A

Semi solids

80
Q

What are the factors considered in choice of ointment base?

A

Site of application (dry wet)
Required rate of drug release
Chemical stability of the drug
Effect of the drug on viscosity of the product

81
Q

Why are drugs prone to hydrolysis not incorporated into water based ointments

A

To avoid degredation