1. Reducing and enlarging formulas

2. Reducing and enlarging formulas
Official formulas and most other formulas are based on the preparation of 1000 ml or 1000 g of product. The pharmacist may be called upon to make either a smaller or greater quantity and thus must reduce or enlarge the formula while maintaining the correct proportion of each ingredient.
Total amount specified = Quantity of each ingredient
in formula in formula
Total amount desired X
X = Quantity of each ingredient in amount desired

3. Reducing and enlarging formulas (Cont.)
Example
From the following formula, calculate the quantities required to make 5 gallons of a Phenobarbital elixir ??
Phenobarbital g
Orange oil ml
Certified red colour Q.S.
Alcohol ml
Propylene glycol ml
Sorbitol solution ml
Water, to make ml

4. Reducing and enlarging formulas (Cont.)
Answer
1- 5 gallons = 128 f-oz x 30 ml x 5 = ml
Enlarging factor = / = 19.2
Phenobarbital = 4 x = g
Orange oil = x = 4.8 ml
Alcohol = x = ml
Propylene glycol = x = 1920 ml
Sorbitol = 600 x = ml
Water to make ml