PTCB Certified Pharmacy Technician (PTCE)MedicationsMedium
A pharmacy technician is preparing to compound a topical cream containing 0.1% triamcinolone acetonide. The prescription requires 60 grams of the cream. How much triamcinolone acetonide powder is needed?
- A6 grams
- B0.006 grams
- C0.06 grams
- D0.6 grams
Show answer & explanationAnswer & explanation
Correct answer: C. 0.06 grams
To calculate the amount of active ingredient needed, convert the percentage to a decimal (0.1% = 0.001) and multiply by the total quantity of the cream (60 grams). So, 0.001 * 60 grams = 0.06 grams.
Why the other options are wrong
- A. This would be 10% of 60 grams, or a calculation error.
- B. This would be 0.01% of 60 grams, or a calculation error.
- D. This would be 1% of 60 grams, or a calculation error.
Percentage Strength Calculation
Percentage strength (w/w, v/v, or w/v) indicates the amount of solute in 100 units of the total mixture. To find the amount of solute, convert the percentage to a decimal and multiply by the total quantity.
- % means 'parts per hundred'.
- For w/w, it's grams of solute per 100 grams of mixture.
- Formula: Amount of solute = (Percentage/100) * Total quantity.
Memory trick: Percent to decimal, then multiply for the part you need.