A prescription calls for 5 mg of morphine sulfate. Using a sensitivity requirement of 5 mg, how would you obtain the required amount of morphine sulfate with an error not greater than 5%?

Step 1 is to calculate the Least Weighable Quantity (LWQ) LWQ = (Sensitivity Requirement ÷ Acceptable Error) × 100 (5 ÷ 5) × 100 5 ÷ 5 = 1 1 × 100 = 100 Result at this step = 100 mg Step 2 is to determine the drug multiplication factor Since the required dose is 5 mg and we must weigh at least 100 mg: Factor = 100 ÷ 5 100 ÷ 5 = 20 Result at this step = 20 Step 3 is to calculate the total mixture weight (drug + diluent) Total Mixture = Aliquot weight × Factor 100 × 20 = 2000 Result at this step = 2000 mg Step 4 is to calculate the amount of diluent needed Diluent = Total Mixture - Drug weight 2000 - 100 = 1900 Result at this step = 1900 mg