EFFECT OF GAMMA-IRRADIATION ON HYDROXYPROPYLMETHYLCELLULOSE POWDERS -CONSEQUENCES ON PHYSICAL, RHEOLOGICAL AND PHARMACOTECHNICAL PROPERTIES

In this paper, we describe a number of hydroxypropylmethylcellulose (H PMC) powders which were subjected to gamma-irradiation and report the results obtained following investigation of their physical properties (coloration, UV and IR spectrometry, calorimetry) and rheological beha viour. The physical properties were not significantly modified on incr easing the irradiation dose. In contrast, the rheological behaviour of the HPMC powders was modified: firstly, the solutions displayed pseud o-plastic behaviour, becoming Newtonian on rupture of the chains with increase in the irradiation dose. Concurrently to this polymeric trans formation, the viscosity of the solutions decreased. HPMC powders, irr adiated at different doses, were used in solution as a binding agent f or granulation during tablet manufacture. The different production sta ges are also described, as well as physical controls (mass, friability , hardness, disintegration) dissolution tests of the active substance from the tablets. No clear modification can be noted.