Pharmacy Technician Certification Board Practice Exam

What quantity of clobetasol propionate is contained within a 30 g tube of clobetasol propionate 0.05% cream?

1. 1.5 g

2. 1.5 mg

3. 15 mg

4. 15 g

The correct answer is: 15 mg

To find the quantity of clobetasol propionate in a 30 g tube of cream that is 0.05% w/w, you need to calculate how much of that total weight is the active ingredient. First, it’s important to understand that a 0.05% concentration means that there are 0.05 grams of clobetasol propionate in every 100 grams of the cream. To determine how much is present in a 30-gram tube, you would set up a proportion based on this percentage. Using the information from the percentage: - 0.05 grams is equivalent to 50 mg (since 1 gram = 1000 mg). - If 0.05 grams is in 100 grams, then in 30 grams, you can set up the calculation: (0.05 g / 100 g) * 30 g = 0.015 g Now, converting 0.015 g to milligrams (since we need mg): 0.015 g x 1000 mg/g = 15 mg Thus, the correct quantity of clobetasol propionate in a 30 g tube of 0.05% cream is 15 mg, making