Stability of solid dosage forms. II. Coloration and photolytic degradation of sulfisomidine tablets by exaggerated ultraviolet irradiation.

Abstract

The solid-state stability of sulfisomidine tablet under the irradiation of ultraviolet rays, was investigated colorimetrically and spectrophotometrically. The coloration of tablet surface was followed in the Lab system in the fade-o-meter. In order to examine the effect of ultraviolet intensity on the rate of coloration and photolytic degradation, a series of glass color filters which shut off the ultraviolet rays in order, were employed. The coloration was found to best fit an apparent second-order degradation equation with respect to colorimetric values. Photolytic degradation was investigated by the semi-integral attenuance spectra in the ultraviolet region. It proceeded following the apparent zero-order kinetics which accompany an induction period. The ultraviolet intensity affected the kinetic constants as well as in the coloration. These degradation behaviors in the solid state were compared with the aqueous solution state.