Enantioselective metabolism of hydroxychloroquine employing rats and mice hepatic microsomes

Hydroxychloroquine (HCQ) is an important chiral drug used, mainly, in the treatment of rheumatoid arthritis, systemic lupus erythematosus and malaria, and whose pharmacokinetic and pharmacodynamic properties look to be stereoselective. Respecting the pharmacokinetic properties, some previous studies indicate that the stereoselectivity could express itself in the processes of metabolism, distribution and excretion and that the stereoselective metabolism looks to be a function of the studied species. So, the in vitro metabolism of HCQ was investigated using hepatic microsomes of rats and mice. The microsomal fraction of livers of Wistar rats and Balb-C mice was separated by ultracentrifugation and 500 mL were incubated for 180 minutes with 10 mL of racemic HCQ 1000 mg mL-1. Two stereospecific analytical methods, high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), were used to separate and quantify the formed metabolites. It was verified that the main formed metabolite is the (-)-(R)-desethyl hydroxychloroquine for both animal species.