Question

What will be the fraction of unbound drug if the unbound drug concentration is 0.99 g/ml and total plasma concentration is 160 g/ml?

(a) 0.006

(b) 1.61

(c) 0.618

(d) 0.010

The question was posed to me during an online interview.

I need to ask this question from Drugs Excretion in section Prodrugs & Excretion of Drugs of Drug Biotechnology

Answer 1

Correct option is (c) 0.618

Best explanation: The fraction of drug bound to plasma proteins can be calculated by the equation fu = Cu/C. Here fu is fraction of unbound drug and Cu is the concentration of unbound drug in plasma and C is the total plasma concentration of the drug. Therefore 99/160=0.618.