Question

A 5 g/100 ml solution of Amphotericin B is stored in a closed test tube at 25°C. If the rate of Amphotericin B degradation is 0.05 g/day, calculate the time required for initial concentration to drop to

(A) 90% of its initial concentration (shelf life)
(B) 50% of its initial concentration (half life)

Answer 1

The time required for the concentration to drop to 90% of its initial concentration is 2 days, and to 50% is 5 days.

Step-by-step explanation:

In order to calculate the time required for the initial concentration of the Amphotericin B solution to drop to certain percentages, we use the equation:

time = (initial concentration - desired concentration) / rate of degradation

For (A) 90% of its initial concentration (shelf life):

time = (5g - 0.9 * 5g) / 0.05g per day = 2 days

For (B) 50% of its initial concentration (half life):

time = (5g - 0.5 * 5g) / 0.05g per day = 5 days