Maths

Question 1

You are working in a pharmacy where you have received a prescription for Rectogesic 0.4 % w/v rectal ointment for a patient with anal fissures. The prescription requests that you supply 120 g of this rectal ointment. What is the weight of glyceryl trinitrate contained in 120 g Rectogesic ointment if this was prepared extemporaneously? (N.B. Glyceryl trinitrate 4 mg per 1 gram)

A) 400 milligrams

B) 120 micrograms

C) 4.8 grams

D) 480 milligrams

E) 1200 micrograms

Answer 1

D) 480 milligrams

0.4% glyceryl trinitrate therefore 400mg (0.4g x 1000) to convert into milligrams in 100g. in

120g = 120/100 x 400 = 480 milligrams