For an experimental diabetes drug with 90% oral bioavailability and a desired steady-state concentration of 3.0 mg/L, what would be the appropriate loading dose if the volume of distribution is 2 L/kg?

To determine the appropriate loading dose for the experimental diabetes drug, the formula used is:

Loading Dose = Desired Steady-State Concentration × Volume of Distribution × Bioavailability.

In this scenario, the desired steady-state concentration is 3.0 mg/L, the volume of distribution is 2 L/kg, and the bioavailability is 90%, or 0.9 when expressed as a decimal.

First, calculate the loading dose for one kilogram of body weight:

Loading Dose = 3.0 mg/L × 2 L/kg × 0.9

= 3.0 × 2 × 0.9

= 5.4 mg/kg.

To obtain the total loading dose in milligrams for a typical adult weighing, say, 70 kg (which is a common assumption in pharmacology unless otherwise specified), we multiply the per kg dose by the weight:

Total Loading Dose = 5.4 mg/kg × 70 kg

= 378 mg.

To round to a standard administration practice or match the best choice in a list, we can choose 400 mg, which is sufficiently close to the calculated total dose and supports practical dosing guidelines while ensuring therapeutic efficacy.

Choosing the loading dose of 400 mg is appropriate