Crystalline form I of 2-methyl-4-(4-methyl-1-piperazinyl) 10H thieno [2,3-b][1,5]benzodiazepine

Abstract

Crystalline Form I of 2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5]benzodiazepine characterised by x-ray powder diffraction peaks at approximately 9.94, 8.53, 8.19, 6.86, 6.35, 5.47, 4.83, 4.71, 4.53, 4.22, 4.08, 3.82, 3.75, 3.69, 3.50, 3.34, 3.11, 2.94, 2.82, 2.76, 2.59, 2.34, 2.03, 1.92 d (interplanar spacing) values; infrared absorbance bands at approximately 1456, 1365, 905, 757, 662 & 604 cm−3 and having stable colour at ambient conditions of storage; and the process of its preparation comprising at least two repetitive steps of crystallization from one or more organic solvent by dissolving 2-methyl-4 -(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5]benzodiazepine in said solvent and allowing crystallization to occur; wherein in at least one step the solution is purified by treating with a solid adsorbent material and filtering; and wherein in the last step the crystalline material is subjected to drying.

Dependencies are inferred from the claim text.