Preliminary study of the biotransformation of two new drugs, trazodone and etoperidone.

M-Chlorophenylpiperazine (CPP) is formed in the course of biotransformation of trazodone and etoperidone. The biotransformation of the latter compound is more rapid. An enzymatic inhibitor, proadifen (SKF 525A), inhibited the formation of CPP, while an enzymatic inductor, phenobarbital, did not affect it. The elimination rate of CPP was much lower than that of trazodone; its t0.5 was approx. 50-60 min. The pharmacokinetic data may explain well the pharmacological properties of trazodone and etoperidone.