Effect of pressure up to 5.5 GPa on dry powder samples of chlorpropamide form-A

The effect of pressure up to 5.5 GPa on a dry powder sample of chlorpropamide (4-chloro-N-((propylamino)-carbonyl)-benzenesulfonamide), form-A (sp. gr. P2(1)2(1)2(1), a = 9.066 angstrom, b = 5.218 angstrom, c = 26.604 angstrom), was studied in situ in a Merrill-Bassett diamond anvil cell using high-resolution Xray powder diffraction (a synchrotron radiation source at SNBLESRF, Grenoble). No evidence of the polymorphic transformation of chlorpropamide form-A to form-C was observed. The A-C polymorphic transition on tabletting previously reported by Otsuka et al. (1989) is therefore likely to be due to local heating effects. Similarly, the phase transitions of form-A reported by Cao (2002) to be induced by pressure applied to a sample in its saturated ethanol solution (at 0.9 and at 2.0 GPa) would appear to be solvent-mediated. In the dry sample, a phase transition may be supposed to occur at pressures above 4 GPa, but this requires further studies. (c) 2006 Elsevier B.V. All rights reserved.