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Stage 3 Case 3 > Ointments > Flashcards

Ointments Flashcards

1
Q

What is an ointment?

A

A semi-solid dosage form, usually anhydrous with a hydrophobic oily base, intended for external application to the skin or mucous membrane.

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2
Q

Ointments are Occlusive

A

Increases skin hydration by minimising transepidermal water loss. Also enhances dermal drug penetration.

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3
Q

Ointment are Emollient

A

Suitable for dry skin

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4
Q

3 types of ointment

A

– Hydrophobic (oleaginous) ointment

– Water emulsifying ointment

– Hydrophilic (greaseless) ointment

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5
Q

Hydrocarbon bases for hydrophobic ointment characteristics (3)

A

– Occlusive—emollient effect

– Not water-washable

– Greasy

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6
Q

Hydrocarbon bases for hydrophobic ointment example

A

Petrolatum (paraffin)

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7
Q

Absorption bases for water emulsifying (W/O) ointment characteristics (4)

A

– Form w/o emulsions with skin secretions.

– W/O emulsifier

– Emollient effect

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8
Q

Absorption bases for water emulsifying (W/O) ointment example

A

Lanolin and derivatives

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9
Q

Water-removable bases for water emulsifying (O/W) ointment characteristics (3)

A

– Form O/W emulsions with skin secretions.

– O/W emulsifier

– Water-washable

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10
Q

Water-removable bases for water emulsifying (O/W) ointment example

A

Cetostearyl alcohol, cetomacrogol.

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11
Q

Water-soluble bases for hydrophilic ointment characteristics (2)

A

– Water-washable

– Non-greasy

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12
Q

Water-soluble bases for hydrophilic ointment example

A

Macrogols (polyethylene glycols = PEG)

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13
Q

2 basic comportments of an ointment

A

Drug

Ointment base

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14
Q

Ointments may also contain (3)

A

Solvent

Antioxidant

Emulsifying agent

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15
Q

Solvent purpose in ointment

A

to dissolve components, miscible with ointment base.

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16
Q

Antioxidant purpose in ointment

A

to prevent oxidative degradation. (reacidification)

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17
Q

Emulsifying agent purpose in ointment

A

for water emulsifying ointments.

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18
Q

Why are preservatives not generally required in ointments

A

As no water content.

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19
Q

Betnovate ointment

A

For relief of inflammatory and pruritic manifestations of steroid-responsive dermatoses.

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20
Q

White soft paraffin purpose in Betnovate

A

Ointment base

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21
Q

Liquid paraffin purpose in Betnovate

A

Ointment base

22
Q

White soft paraffin purpose in Fucidin Ointment

A

Ointment base

23
Q

Liquid paraffin purpose in Fucidin Ointment

A

Ointment base

24
Q

All-rac-alpha-tocopherol ​purpose in Fucidin Ointment

A

Vitamin E antioxidant ​

25
Q

Butylhydroxytoluene purpose in Fucidin Ointment

A

Antioxidant ​

26
Q

Cetyl alcohol purpose in Fucidin Ointment

A

Emulsifier ​

27
Q

Lanolin (wool fat) purpose in Fucidin Ointment

A

Ointment base

28
Q

Rancidification

A

Oxidative chain reaction mediated by free radicals, changing organoleptic properties due to chemical decomposition.

29
Q

What does rancidification happen to?

A

Particularly to oxygen-containing fats and oils derived from animals or plants.

30
Q

How do antioxidants work?

A

Deplete free radicals, thus terminating oxidative chain reactions. Needs to be soluble in ointment base.

31
Q

Example of water emulsifying ointment

A

Fucidin Ointment

32
Q

Fucidin Ointment

A

Treatment of skin infections caused by sensitive strains of S. aureus, streptococcus spp and Corynebacterium minutissimum.

33
Q

How to incorporate a drug into an ointment (3)

A
  • Dissolve directly in ointment base.
  • Dissolve drug in a suitable solvent, then incorporate solution into ointment base.
  • Levigate solid drug into ointment base to disperse evenly, with geometric dilution.
34
Q

What is levigation?

A

Crushing particles in presence of a fluid (levigation fluid) to reduce particle size as it being incorporated into ointment.

35
Q

Two types of penetration enhancers

A

Physical and chemical

36
Q

Chemical penetration enhancer (CPE) auxiliary equipment?

A
  • Included as an excipient in formulation.

- No requirement for auxiliary equipment.

37
Q

Physical enhancement auxiliary equipment?

A

Usually requires auxiliary equipment.

38
Q

Physical enhancement examples

A

Microneedles, iontophoresis, electroporation, sonophoresis, laser ablation, thermal ablation.

39
Q

Chemical penetration enhancer (CPE) increase permeability by…

A

Drug partitioning

40
Q

What does the Lipid-protein-partitioning theory propose

A

Proposes that the skin has lipophilic and hydrophilic domains.

41
Q

Lipid-protein-partitioning theory: lipid

A

Disrupting stratum corneum lipids (lipophilic domain), increasing diffusivity (D) for lipophilic drugs.

42
Q

Lipid-protein-partitioning theory: Protein

A

Altering stratum corneum proteins (hydrophilic domain), increasing diffusivity (D) for hydrophilic drugs.

43
Q

Lipid-protein-partitioning theory: Partitioning

A

Enhancing drug partitioning from formulation into skin, increasing partitioning (K).

44
Q

Ideal properties of penetration enhancers (2)

A

– Chemically inert and non-toxic.

– Transient, reversible and selective penetration enhancement effect.

45
Q

What type of molecules act as strong chemical penetration enhancers

A

Amphiphilic compounds that have a polar head group and long hydrocarbon tail.

46
Q

What do Amphiphilic compounds resemble in relation to the skin?

A

Stratum corneum (SC) lipids

47
Q

How do amphiphilic compounds work as chemicals penetration enhancers?

A

Insert into SC extracellular lipids to loosen packing.

48
Q

Examples of amphiphilic compounds as chemicals penetration enhancers

A

Surfactants, fatty alcohols, fatty acids, phospholipids.

49
Q

What type of amphiphilic compounds are most effective as chemicals penetration enhancers?

A

Unsaturated (double bond) and cis hydrocarbon tail more effective.

50
Q

Why are cis isomers more effective than unsaturated (trans)?

A

The cis has a kink which forces open a gap in the SC lipid structure which allows small molecules to pass through.

51
Q

Polar CPE are more effective on what type of drug?

A

Hydrophilic

52
Q

Non-polar CPE are more effective on what type of drug?

A

Lipophilic

Stage 3 Case 3 (8 decks)

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