PTCB Certified Pharmacy Technician (PTCE)Order Entry and ProcessingEasy
A pharmacy technician is preparing to compound a 2% hydrocortisone cream. The prescription requires 60 grams of the cream. How many grams of pure hydrocortisone powder are needed?
- A1.2 grams
- B12.0 grams
- C3.0 grams
- D0.6 grams
Show answer & explanationAnswer & explanation
Correct answer: A. 1.2 grams
To calculate the amount of hydrocortisone powder needed, multiply the total quantity of the cream by the percentage strength. 2% of 60 grams is 1.2 grams.
Why the other options are wrong
- B. Incorrect calculation; this would be 20% of 60 grams or 2% of 600 grams.
- C. Incorrect calculation; this would be 5% of 60 grams.
- D. Incorrect calculation; this would be 1% of 60 grams or 2% of 30 grams.
Percent Strength Calculation (w/w)
Calculates the amount of solute in a given amount of solution, expressed as a percentage of weight by weight.
- Used for solid-in-solid or liquid-in-liquid preparations where both components are measured by weight.
- Formula: (grams of solute / total grams of solution) * 100%.
- Convert percentage to a decimal (e.g., 2% = 0.02) for calculations.
Memory trick: Percent means 'part of a hundred' by weight.