Study by DSC and HSM of the oxazepam PEG 6000 and oxazepam-D-mannitol systems: Application to the preparation of solid dispersions

Oxazepam is a drug characterised by its marked hydrophobicity and unsatisfa ctory wettability on contact with wafer. These properties lead to incomplet e absorption of the drug from the gastrointestinal tract when the pharmaceu tical dosage form is not adequately formulated. For this reason, it is of i nterest to optimise its dissolution properties. For this purpose, the prepa ration of solid dispersions with hydrophilic carriers has been often employ ed. In this paper, the possibility of employing two hydrophilic substances (PEG 6000 and D-mannitol) as carriers for solid dispersions, prepared by th e co-fusion or the fusion carrier methods, were evaluated by DSC and HSM. T he results show, in terms of the miscibility of molten oxazepam in the fuse d vehicle, that PEG 6000 is the only suitable carrier. D-mannitol yielded n on-homogeneous systems. (C) 1998 Elsevier Science B.V.