Question

How many grams of hydrocortisone should be used in preparing 120 suppositories, each weighing 2 g and containing 0.5% of hydrocortisone?

Answer 1

0.5% of hydrocortisone suppository weighing 2g contains 0.01g of hydrocortisone. See calculation below for clarification

2g of hydrocortisone suppository with concentration of 0.5% means, it contains hydrocortisone as calculated below

= 0.5 ×2g ÷100

=0.01g

Required quantity of hydrocortisone to prepare 120 suppositories ( weighing 2g each with 0.5% of hydrocortisone) as below

For each suppository 0.01g required

For 120 suppositories= 120 × 0.01g

=1.2g

Finally to prepare 120 suppositories weighing 2g containing 0.5% of hydrocortisone requires 1.2g of hydrocortisone.