Synthesis of highly potent novel anti-tubercular isoniazid analogues with preliminary pharmacokinetic evaluation

Abstract

Thirty two novel isoniazid analogues were prepared by one-pot three component condensations of isoniazid (INH), 3-mercaptopropionic acid and various aryl/heteroaryl aldehydes. The synthesized compounds were evaluated for their anti-TB activity against Mycobacterium tuberculosis H37Rv (MTB) and cytotoxicity. Among the compounds, compound N-(2-(4-(benzyloxy) phenyl)-4-oxo-1,3-thiazinan-3-yl) isonicotinamide (17) inhibited MTB with MIC of 0.12 μM and was three times more potent than INH. The main pharmacokinetic parameters after intravenous administration (10 mg/kg body weight) in male Wistar rats viz. t(½), K(el), mean plasma clearance and mean volume of distribution were found to be 1.14±0.20 h, 0.62±0.10 h(-1), 22.48±0.16 mL/kg/min and 1.99±0.49 L, respectively. The systemic absorption was slow after oral administration (50 mg/kg body weight). The peak plasma concentration was found to be 1.31±0.06 μg/mL attained in 3 h. The bioavailability was found to be 16.7%.