A 75kg adult male human was dosed with 200mg of compound X. His initial plasma concentration of the compound was 30 mg/L. After 3 hours, the plasma concentration of compound X is 5 mg/L. Explain all answer.
a) Increased metabolism of compound X in the body
b) Decreased elimination of compound X by the kidneys
c) Redistribution of compound X into tissues
d) Combination of increased metabolism and redistribution