A ciprofloxacin otic solution contains 0.5 mg of ciprofloxacin in a 0.25-mL single-dose package. Based on 20 drops/mL,

Question

(a) how many drops would be administered and (b) how many micrograms of ciprofloxacin would be in each drop?

Answer 1

Part a)

First find the concentration: 0.5 mg/0.25mL = 2 mg/mL

One dose = 0.25 mL x 20 drops / mL = 0.25 x 20 drops = 5 drops

Part b)

1 mL/20 drops x 2 mg/mL x 1000 µg/mg = 100 µg in one drop