Cocrystallization of methyltestosterone with salicylic acid and 2,2′-disulfanediyldibenzoic acid - Effect on solubility of methyltestosterone and growth of leishmania parasite (amastigotes and promastigotes)

Abstract

Methyltestosterone is a class II anabolic androgenic steroidal drug, structurally resembled to natural testosterone, produced by body. Two cocrystals of methyltestosterone with thiosalicylic acid and salicylic acid were successfully furnished by using solid state grinding method with the aim to study changes in biological activities and solubility. During cocrystallization the coformer thiosalicylic acid dimerize into 2, 2′-disulfanediyldibenzoic acid and furnished co-crystal I. Characterization of cocrystals 1 and II was carried out on the basis of single-crystal X-ray diffraction technique, IR spectroscopy, DSC/TGA analysis. The solubility of prepared cocrystals I and II were found to be significantly improved in different dissolution media i.e. phosphate buffer (pH 6.8, 7.4), 0.1 N HCl and distill water. Methyltestosterone and both cocrystals were found to be non-cytotoxic while tested against BJ human normal fibroblast cell line. Non-cytotoxic cocrystals I and II were further evaluated for anti-leishmanial activity (amastigotes and promastigotes). Both cocrystal I (IC50 = 11.9 µM) and II (IC50 = 27.2 µM) shows potent anti-leishmanial activity against L. major promastigote (extracellular / in blood parasite stage) and amastigote (intracellular / inside macrophage cell) stage in comparison to the standard drugs miltefosine (IC50 = 25.5 ± 0.42 µM) and methyltestosterone (IC50 = 37.42±0.57 µM). Infected macrophage cellular assay together with AFM analysis are carried out to study the effect of synthesized cocrystals on growth of amastigotes stage of L. major. The promising result demonstrates the effect of cocrystallization on solubility and anti-leishmanial potential of anabolic androgenic steroidal drug methyltestosterone for the first time.