Question

In patient studies, the ability to secrete a new drug, compound BME330 (“CBME330”), plasma concentrations after the drug ingestion were measured at 35 mg/liter. The clearance of CBME330 was determined to be 80 ml/min. The inulin clearance was 120 ml/min. Calculate the excretion rate (in mg/min) of CBME330.

Total Body Water = 42L

Extracellular Fluid = 14L

Osmolarity = 300mOsmoles/L

Intracellular Fluid = 28L

Answer 1

ANSWER.

Calculation of excretion rate.

Formula

    Excretion rate(mg/min) = Plasma drug concentration(mg/ml) * Clearance(ml/min).

Here

     Plasma drug concentration = 35 mg/l.

Convert mg/l to mg/ml for calculation by divide with 1000.

      So

          Plasma drug concentration = 35/1000

                                                       = 0.035 mg/ml.

                         Clearance = 80 ml/min.

As per above formula

         Excretion rate = 0.035 * 80

                                = 2.8 mg/min.