Lec 3 External preparations

Question 1

What is an ointment?

Answer 1

Oily vehicles with surgactant so can be washed off easily

- Used as emollients (soften tissues), for drug delivery to the surface or deeper penetration into skin

Question 2

What are creams?

Answer 2

• Usually oil in water emulsions (oily creams are water in oil emulsions)
• Less greasy than ointments used for drug delivery onto or into skin
• High water content so require preservative

Question 3

What are pastes?

Answer 3

• High concentration of added solids
• Makes them thick and localises drug delivery
  Eg. Sun block

Question 4

What are gels?

Answer 4

• Aqueous gels for lubrication or drug application to the skin
• Oily gets used for occulsion (excludes air, retains moisture, heat, body fluids and medicaments)

Question 5

Application (definition, example, label)

Answer 5

• a liquid or semi-solid preparation for external use
  Eg. Benzyl benzoate application
• for external use only

Question 6

Ear drops (definition, example, label)

Answer 6

• solution of medicament in water, glucerol, propylene glycol or diluted ethanol
  Eg. Sodium bicarbonate ear drops
• Caution: Not to be taken

Question 7

Gel (definition, example, label)

Answer 7

• water-miscible, viscous preparations for application
  Eg. Chlorhexidine gel
• For external use only

Question 8

Lotion (definition, example, label)

Answer 8

• liquid preps for application to skin without friction
  Eg. Calamine lotion
• For external use only

Question 9

Paint (definition, example, label)

Answer 9

• Liquid prep for application in limited amounts to skin or mucous surface
  Eg. Salicyclic acid paint
• For external use only

Question 10

Liniment (definition, example, label)

Answer 10

• Liquid or semi-liquid prep for external application containing analgesic, rubefacient, soothing or stimulating properties
  Eg. Methyl salicylate compound liniment
• For external use only, do not apply to broken skin

Question 11

Paste (definition, example, label)

Answer 11

• Solid external prep with protective properties
  Eg. Zinc paste
• For external use only

Question 12

Shampoo (definition, example, label)

Answer 12

• Liquid or soapy solution for scalp or body
  Eg. Nizoral shampoo
• Not to be taken. External use only

Question 13

Suppository (definition, example, label)

Answer 13

• Solid unit dose shaped for rectal administration with medicament for local or systemic effect
  Eg. Paracetamol suppository
• For rectal use only, unwrap before use

Question 14

Creams (definition, example, label)

Answer 14

• Semi-solid prep, usually emulsions for application to skin
  Eg. Aqueous Cream
• For external use only

Question 15

Nose drops (definition, example, label)

Answer 15

• Liquid preparation for use in nasal possages
  Eg. Otrivine
• Caution: not to be taken

Question 16

Ointments (definition, example, label)

Answer 16

• Semi-solid preparations used as emollients, protective preparations or to provide medicatment to skin
  Eg. Emulsifying Ointment
• For external use only

Question 17

Where do medication on skin pass?

Answer 17

• Stratum corneum, hair follicles, sweat glands
• Lipid soluble -> lipid regions
• Water soluble -> enter blood capillaries
• Absorption occurs-> may cause toxicity

Question 18

How does skin treatment work?

Answer 18

By drugs or by creating physiological changes

• normal skin 10-25% moisture
• evaporation = cooling (for inflammation)

Question 19

What is it called when there is a lack of moisture on skin and what product is used?

Answer 19

Eczema

• Use occlusive, oily product as emollient
• Oitment to hydrate and soften the skin

Question 20

What is it called when there is too much moisture on skin and what product is used?

Answer 20

Athlete’s foot

- Use astringent, non oily medicated cream

Question 21

Name 3 water-miscible vehicles

Answer 21

1. Water
2. Alcohol (industrial denatured alcohol)
3. Macrogols (liq/semi-solid to waxy solids)

Question 22

Name 3 oily vehicles

Answer 22

1. Minteral oils (paraffins) - soft paraffin
2. Vegatable oils- castor, oil, peanut and coconut oils. Occlusive, skin penetration, may cause allergic reactions
3. Synthetic oils water repellant and occlusive

Question 23

Name 3 emulsifying agents and describe

Answer 23

1. Oil in water: emulsifying waxes, mix with oily materials, add water to form a cream, easily washed off skin
2. Water in oil- wool fat, wool alcohol, beeswax, increase water holding capacity of greasy bases

Other
Water in oil emulsions: calcium soaps
Oil in water emulsions: soft soap
Water in oil emulsions: synthetic low HLB
Oil in water emulsion: synthetic high HLB

Question 24

What are suspending agents used for?

Answer 24

For suspending solids in a lotion or to produce gels

Question 25

What are clays (suspending agent)?

Answer 25

- bentonite | - leave a lubricant layer of powder on skin

Question 26

What are gelling agents? (suspending agent)

Answer 26

- give a range of consistency | - tragacanth, methylcellulose, alginates for aqueous gels, cetostearyl alcohol and beeswax for oils

Question 27

What are wetting agents?

Answer 27

For hydrophobic solids | Eg. Tinct of quillaia

Question 28

What are humectants?

Answer 28

Reduce the rate of water loss from a cream and gel | Eg. propylene glycol, glycerol, sorbitol, syrup

Question 29

What are solids for?

Answer 29

- added to semi-solic occlusive bases to reduce occlusiveness Eg. Zinc oxide, talc, starch

Question 30

What does dusting powders mean?

Answer 30

- Mix in motal with pestle using doubling up technique | - may need to sieve

Question 31

What are liquid preparations used to make?

Answer 31

Solutions, suspensions and emulsions

Question 32

What are ways of semi-solid preparation?

Answer 32

1. Mixing by fusion | 2. Mixing by trituration

Question 33

Describe Mixing by fusion and how it is done

Answer 33

- Many oily materials are solid at room temperature (waxes) - Mix by melting ingredients in evaporating dish in water bath (60-70 degrees) - Waxy solids grated first and melted first - When melted, remove heat, stir gently to avoid air bubbles until cold - Medicament added at different stages according to solubility and stability - Recovery of all the product may not be possible (prep 10% excess)

Question 34

What are ointments?

Answer 34

Semi-solid preparations which may contain a medicament or mixture of medicaments dissolved or dispersed in a suitable greasy base Used as: 1. Emollients 2. Protective preparations on the skin 3. Local application of medicaments

Question 35

What kind of creams are there?

Answer 35

1. Aqueous cream: water miscible - > effectively deliver medicaments to body surface 2. Oily creams: oil miscible - > protective and emollient cream 3. Surface active agents: Cationic (+ve), anionic (-ve) and non ionic

Question 36

What are the steps of compounding creams by fusion?

Answer 36

1. Water bath- heat waxes and oils separately to the water and dissolve watersoluble ingredients (60-70 degrees) 2. Insoluble ingredients: incorporate on glass slab by trituration 3. Grate waxes if necessary. Add oils last 4. Add water to oil at same temperature 5. Cool slowly with stirring to avoid lumps

Question 37

What are the features of aqueous cream?

Answer 37

Light emollient used to soothe, smooth and hydrate the skin and are indicated for all dry or scaling disorders - need to be applied frequently - aq cream can be used as a soap substitute

Question 38

What does menthol do in cream?

Answer 38

- soothes and cools skin - dilates blood vessels, causing a sensation of coldness followed by an analgesic effect - > relieves itching and is used in creams, lotions, or ointments in pruritus and urticaria