In Vitro approach for identification of a leading cytochrome P450 isoenzyme responsible for biotransformation of novel arylpiperazine drug candidates and their inhibition potency towards CYP3A4.

The aim of this study was to identify cytochrome P450 (CYP) isoforms that participate in the metabolism of some novel arylpiperazine derivatives developed by authors as well as their potency to inhibit reactions catalyzed by identified lead metabolizing enzyme. Such studies allow to predicting possible drug-drug interactions that might occur during co-administration of studied compounds with other drugs that are metabolized by an identified enzyme. The compounds were incubated in vitro together with the isolated CYP isoforms. After the incubation, samples were analyzed by liquid chromatography coupled with mass spectrometry. The results showed the main contribution of CYP3A4 isoform in biotransformation of the investigated derivatives. With CYP3A4 being the main CYP isoform responsible for the metabolism of arylpiperazine derivatives and at the same time being the main metabolizing enzyme for almost 50% of all drugs, a high chance of in vivo drug-drug interactions emerged. Therefore, IC50 values were also determined using testosterone hydroxylation as a probe reaction, specific for CYP3A4. The resulting values ranged from 6.13 to 15.85 mu M, which places studied derivatives as moderate or weak inhibitors of CYP3A4. Those results, combined with the conclusion that all of the arylpiperazine derivatives are also metabolized to some extent by other CYP isoforms (providing alternative metabolic pathways), result in a conclusion that studied arylpiperazines might be safe for co-administration with other CYP3A4 substrates.