Lec 2 Extemporaneous compounding Flashcards

1
Q

What is extemporaneous compounding?

A

Medicines made from scratch, individual ingredients mixed together in the exact strength and dosage from required by the patient
-> allows compounding pharmacist to work with the patient and the prescriber to customize a medication to meet the patient’s specific needs

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2
Q

What is mixing by triturations?

A
  • Incorporating FINELY DIVIDED insoluble powders or liquids into a base
  • performed on a glass slab or tile
  • liquid incorporated by making a ‘well’ into the centre of base, with small amounts of liquid poured into well and mixed in
  • avoid air pockets
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3
Q

What is mixing by levigations?

A
  • Incorporation of insoluble COURSE powders into a base- can be called ‘wet grinding’
  • the powder is rubbed down with either a molten base or a semi-solid base
  • Shearing force with the flat blade of the spatual against the slab needs to be applied to avoid a gritty product
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4
Q

What is the ‘doubling-up’ technique?

A
  • Mixing powder to powder, powder to semi-solid or semi-solid to semi-solid, especially when one amount is much smaller than the other
  • Can be done in a motar (powder to powder) or on the slab
  • Start with small amount of each, mix thoroughly, then double the volume each time as you continue to add to equal what has been mixed
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5
Q

How to add solids and liquids to a semi-solid base?`

A
  1. Place weighed semi-solid base on glass slab
  2. Place all weighed solids in motar and mix or place on glass slab and mix
  3. Use doubling up technique to incorporate solids into base using a spatula
  4. When mixed well in centre, carefully put in small amounts of liquid and mix within the well or score to mix
  5. Continue until all liquid well mixed in
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6
Q

What is an emulsion?

A
  • A thermodynamically unstable system consisting of at least 2 immiscible liquid phases
  • one phase is dispersed as globules (dispersed phase) in the other liquid (continuous phase) stabilised by an emulsifying agent
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7
Q

How do you make an emulsion?

A
  • Using a motar and pestle to mix oil, water and emulsifying agent to make a primary emulsion using dry and wet methods
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8
Q

What gum is used to make oral emulsions?

A
Acacia 
Primary emulsion: Oil: Water: Gum 
- Fixed oils = 4: 2: 1
- Mineral oils= 3: 2: 1
- Volatile Oils= 2: 2: 1
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9
Q

What is the dry gum method?

A
  1. Use a clean, DRY motar with a flat bottom
  2. Drain oil (measure carefully)
  3. Disperse acacial over oil and mix gently
    4, Add water all at once and stir briskly in one direction –> Clicking sound = primary emulsion formed- white in colour
  4. Gradually dilute primary emulsion with vehicle and dissolved ingredients
  5. Transfer to pre-calibrated bottle and label
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10
Q

What is the wet gum method?

A
  1. Add water to acacia gum and mix gentaly to make a mucilage
  2. Add oil in small maounts to mucilage
  3. Triturating thoroughly after each addition until a thick primary emulsion is formed
  4. Stabilise by mixing for several minutes then add other ingredients as for dry gum method
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11
Q

What are some problems when compounding an emulsion?

A
  • Phase inversion
  • Incorrect quantities of oil or water used
  • Cross contamination of water/oil
  • Wet motar used
  • Motar too small and curved, head of pestle too rounded- insufficient shear force
  • Excessive mixing at first stage with dry gum method and oil
  • Diluting primary emulsion too soon and too rapidly
  • Poor quality acacia
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12
Q

What is a suspension?

A

A disperse system in which one substance in the disperse phase is distributed in particulate form throughout another (the continuous phase)
- Suspended solids slowly seperate on standing, and can usuallly be redispersed with shaking but this may be difficult if they form a compacted sefiment

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13
Q

How to make a suspension base?

A
  1. Use motar and pestle to grind tablets

2. Mix with glycerol, syrup or mucilage

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14
Q

How do you dispense powders?

A
  1. Use motar and pestle to mix active ingredient with filler using double up method
  2. Wrap powders and fill capsules
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15
Q

What are capsules?

A
  • solid preparations for oral administration (hard or soft and medicaments enclosed within the shell)
  • Soft capsules are formed, filled and sealed in one process and requires specialised equipment
  • Give accurate dose and improved stability
  • Used for powders, non aq liquids, solutions, emulsions, suspensions or pastes
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16
Q

What are the advantages of single-dose powders?

A
  1. Small particle size of drug
  2. Acceptable to patient
  3. Easy to give
  4. Accurate dosing
  5. Stable
17
Q

What are the disadvantages of single-dose powders?

A
  1. Maybe difficult to swallow
  2. Hard to mask taste
  3. Calculations needed
  4. Time to dispense
18
Q

What are the advantages of capsules?

A
  1. Taste easily masked
  2. Release can be controlled
  3. Made light resistant
  4. Easy to swallow
  5. Good for identification
19
Q

What are the disadvantages of capsules?

A
  1. Difficult to swallow
  2. Not for small children
  3. Animal gelatin in caps
20
Q

Filling capsules

A
  1. Aware of hygiene
  2. tare before filling each capsule
  3. Put in small, dry glass or plastic bottle
  4. Storage: coold dry place, dessicant may be needed
    Advice: swallow whole with water