Reducing and enlarging formulas

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

Reducing and enlarging formulas (Cont.) Example From the following formula, calculate the quantities required to make 5 gallons of a Phenobarbital elixir ?? Phenobarbital 4 g Orange oil 0.25 ml Certified red colour Q.S. Alcohol 200 ml Propylene glycol 100 ml Sorbitol solution 600 ml Water, to make 1000 ml

Reducing and enlarging formulas (Cont.) Answer 1- 5 gallons = 128 f-oz x 30 ml x 5 = 19200 ml Enlarging factor = 19200 / 1000 = 19.2 Phenobarbital = 4 x 19.2 = 76.8 g Orange oil = 0.25 x 19.2 = 4.8 ml Alcohol = 200 x 19.2 = 3840 ml Propylene glycol = 100 x 19.2 = 1920 ml Sorbitol = 600 x 19.2 = 11520 ml Water to make 19200 ml