Pharmaceutical Calculations and Compounding Flashcards
6 cards from real Pharm.D. Doctor of Pharmacy practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pharmaceutical Calculations and Compounding flashcards as text
A pharmacist prepares a compound by mixing 30 g of a 2.5% hydrocortisone cream with 70 g of a plain base. What is the final concentration?
Answer: 0.75%
Active drug = 30 g × 0.025 = 0.75 g; total weight = 100 g; final concentration = 0.75/100 = 0.75%.
Which type of balance is most commonly required by USP standards for prescription compounding?
Answer: Class A prescription balance (sensitivity: 6 mg)
USP requires a Class A prescription balance with a sensitivity requirement (SR) of 6 mg for compounding prescriptions involving small quantities.
The beyond-use date (BUD) for a non-aqueous compounded preparation in a non-sterile environment, per USP , is:
Answer: 6 months or shelf life of the ingredient, whichever is earlier
USP sets the BUD for non-aqueous preparations at the earlier of 6 months or the shortest remaining shelf life of any ingredient.
Alligation medial is used to calculate:
Answer: The strength of a mixture of two concentrations of the same drug
Alligation medial (or alternate) is a mathematical shortcut to determine the proportions needed to mix two strengths of a substance to achieve a desired intermediate strength.
A prescription calls for 240 mL of a 1:400 w/v solution. How many grams of drug are required?
Answer: 0.6 g
1:400 means 1 g per 400 mL; for 240 mL: (1/400) × 240 = 0.6 g.
Reducing particle size during compounding through trituration in a mortar and pestle primarily achieves:
Answer: Enhanced dissolution rate and uniformity of mixing
Trituration reduces particle size, increasing surface area, which enhances dissolution rate and ensures homogeneous distribution throughout the preparation.