Chapter 4: Emulsions
16. Castor oil 30% v/v emulsion
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11. Make up to volume with any remaining Double Strength Chloroform Water BP and freshly boiled and cooled purifi ed water.
12. Stir and transfer to an amber fl at medical bottle label and dispense.
5. A plain amber bottle with a child-resistant closure would be most suitable as the preparation is for internal use.
6.
a. The product is unoffi cial, therefore the following title would be suitable:
‘Maize oil 30% v/v emulsion’.
b. Quantitative particulars are required as the product is unoffi cial. The quantitative particulars would be expressed per dose (i.e. per 15 ml):
Each 15 ml contains:
Maize oil BP 4.5 ml
Acacia BP 1.125 g
Double Strength Chloroform Water BP 7.5 ml Freshly boiled and cooled purifi ed water to 15 ml
c. ‘Shake the bottle’ will need to be added to the label as the product is a emulsion and will need shaking before use to ensure an accurate dose is measured.
d. ‘Take THREE 5 ml spoonfuls THREE times a day.’
e. Not applicable.
f. This product is an emulsion and would attract a 4-week discard date.
g.
Maize oil 30% v/v emulsion 100 ml
Take THREE 5ml spoonfuls THREE times a day.
Do not take after (4 weeks) Shake the bottle Each 15 ml contains:
Maize Oil BP 4.5 ml
Acacia BP 1.125 g
Double Strength Chloroform Water BP 7.5 ml Freshly boiled and cooled purifi ed water to 15 ml
Miss Sophie Jones Date of dispensing
7. The patient would be advised to take three 5 ml spoonfuls three times a day. In addition, the discard date and the need to shake the bottle before use would be highlighted to the patient.
Product formula
Master 50 ml
Castor Oil BP 30 ml 15 ml
Acacia BP qs qs
Double Strength Chloroform Water BP 50 ml 25 ml Freshly boiled and cooled purifi ed water to 100 ml to 50 ml
Need to calculate the quantity of emulsifying agent (Acacia BP) required to produce 50 ml of the emulsion.
Formula for primary emulsion
Castor oil is a fi xed oil. Therefore the primary emulsion ratio is:
Oil : Water : Gum
4 : 2 : 1
15 ml of Castor Oil BP is required, therefore 4 parts = 15 ml.
1 part will therefore be 15 ÷ 4 = 3.75.
Therefore:
The amount of freshly boiled and cooled purifi ed water needed = 2 × 3.75 ml = 7.5 ml.
The amount of acacia required = 3.75 g.
Therefore the product formula for 50 ml of castor oil 30% emulsion is:
50 ml
Castor Oil BP 15 ml
Acacia BP 3.75 g
Double Strength Chloroform Water BP 25 ml Freshly boiled and cooled purifi ed water to 50 ml
Interim formula for Double Strength Chloroform Water BP
Concentrated Chloroform Water BPC 1959 2.5 ml
Freshly boiled and cooled purifi ed water to 50 ml 4.
a. No solids will need to be dissolved during the preparation of this product.
b. As emulsions are particularly susceptible to microbial contamination, Double Strength Chloroform Water BP will be used as the vehicle at a concentration of 50%. Freshly boiled and cooled purifi ed water will be used as the remainder of the vehicle. As freshly boiled and cooled purifi ed water is used in the product, it will also be used to make the Double Strength Chloroform Water BP.
c. Double Strength Chloroform Water BP is included in this product as the preservative as per the product formula.
d. No extra fl avouring is required. In addition to preservative action Double Strength Chloroform Water BP will give some fl avouring.
The following method would be used to prepare 50 ml of castor oil 30% v/v emulsion from the formula above:
1. Calculate the composition of a convenient quantity of Double Strength
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Chloroform Water BP, suffi cient to satisfy the formula requirements but also enabling simple, accurate measurement of the concentrated component.
Method of compounding for Double Strength Chloroform Water BP
a. In this case, 25 ml of Double Strength Chloroform Water BP is required and so it would be sensible to prepare 50 ml. To prepare 50 ml Double Strength Chloroform Water BP, measure 2.5 ml of Concentrated Chloroform Water BPC 1959 accurately using a 5 ml and a 1 ml syringe.
b. Add approximately 45 ml of freshly boiled and cooled purifi ed water to a 50 ml conical measure (i.e. suffi cient water to enable dissolution of the concentrated chloroform component without reaching the fi nal volume of the product).
c. Add the measured Concentrated Chloroform Water BPC 1959 to the water in the conical measure.
d. Stir gently and then accurately make up to volume with freshly boiled and cooled purifi ed water.
e. Visually check that no undissolved chloroform remains at the bottom of the measure.
2. Measure 15 ml of Castor Oil BP.
3. Transfer to a clean dry porcelain mortar.
4. Weigh 3.75 g Acacia BP on a Class II balance.
5. Transfer to the mortar and mix gently (approx 3 stirs) to wet the acacia in the oil.
6. Measure 25 ml Double Strength Chloroform Water BP.
7. Measure 7.5 ml of Double Strength Chloroform Water BP (from the 25 ml in step 6) in an appropriate measure and add to the mortar in one go.
8. Stir vigorously using the pestle in one direction until the primary emulsion is formed.
9. Add more Double Strength Chloroform Water BP little by little until the emulsion is pourable.
10. Transfer to an appropriate conical measure with rinsings.
11. Make up to volume with any remaining Double Strength Chloroform Water BP and freshly boiled and cooled purifi ed water.
12. Stir and transfer to an amber fl at medical bottle label and dispense.
5. A plain amber bottle with a child-resistant closure would be most suitable as the preparation is for internal use.
6.
a. The product is unoffi cial, therefore the following title would be suitable: ‘Castor oil 30% v/v emulsion’.
b. Quantitative particulars are required as the product is unoffi cial. The quantitative particulars would be expressed per dose (i.e. per 20 ml):
Each 20 ml contains:
Castor Oil BP 6 ml
Acacia BP 1.5 g
Double Strength Chloroform Water BP 10 ml Freshly boiled and cooled purifi ed water to 20 ml
Answers to self-assessment
c. ‘Shake the bottle’ will need to be added to the label as the product is a emulsion and will need shaking before use to ensure an accurate dose is measured.
d. ‘Take FOUR 5 ml spoonfuls at night.’
e. Not applicable.
f. This product is an emulsion and would attract a 4-week discard date.
g.
Castor oil 30% v/v emulsion 50 ml
Take FOUR 5ml spoonfuls at night.
Do not take after (4 weeks) Shake the bottle Each 20 ml contains:
Castor Oil BP 6 ml
Acacia BP 15 g
Double Strength Chloroform Water BP 10 ml Freshly boiled and cooled purifi ed water to 20 ml
Ms Petra Williams Date of dispensing
7. The patient would be advised to take four 5ml spoonfuls at night. In addition, the discard date and the need to shake the bottle before use would be highlighted to the patient.