Structural characterization of anhydrous naloxone- and naltrexone hydrochloride by high resolution laboratory X-ray powder diffraction and thermal analysis
Abstract
The crystal structures of the analgesic compounds anhydrous naloxone and naltrexone hydrochloride were determined ab initio from high resolution laboratory X-ray powder diffraction data. Both compounds crystallize in the orthorhombic space group P212121 with lattice parameters of a = 14.6588(10) Å, b = 17.4363(9) Å, c = 7.96200(22) Å, and V = 2035.06(23) Å3 for naloxone hydrochloride and a = 15.4560(5) Å, b = 14.9809(4) Å, c = 7.84121(18) Å, and V = 1815.58(11) Å3 for naltrexone hydrochloride. The crystal structure of anhydrous naloxone hydrochloride forms one-dimensional chains through hydrogen bonds. In the crystal structure of anhydrous naltrexone hydrochloride, two-dimensional sheets are formed by hydrogen bonds. The dehydration processes of naloxone hydrochloride dehydrate and naltrexone hydrochloride tetrahydrate was analyzed by DTA, DSC, TG, and MG. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 3316–3323, 2007
