INTERACTION OF TEMAZEPAM WITH CERTAIN MACROMOLECULES: IV- PHASE DIAGRAM OF TEMAZEPAM-POLYETHYLENE GLYCOL BINARY SYSTEMS

Document Type : Original Article

Authors

1 School of Pharmacy, Bradford University, England

2 Department of Industrial Pharmacy, Faculty of Pharmacy, Assiut University, Assiut, Egypt

Abstract

Differential scanning calorimetery and hot stage microscopy were used to build up temperature-composition phase diagrams for temazepam-polyethylene glycol 2000, 4000 and 6000 physical mixtures and comprecipitates.
The phase diagram showed the systems to be of the monotectic type, with the monotectic species being the pure drug.
Phase diagram of the drug and the investigated polyethylene glycols helped in ruling out the possibility of forming solid solution or molecular compound within the concentration range of the components investigated.
Differential scanning calorimetery was also utilized for predicting the melting behaviour of temazepam and polyethylene glycols separately and as coprecipitates and physical mixture binary systems.
A good correlation was found between the position of the system on the phase diagram and its dissolution rate. The highest the carrier content, the nearest the system would be to the monotectic composition, the highest the release rate of the drug.