DETERMINATION OF MULTICOMPONENT DISSOLUTION PROFILES OF PHARMACEUTICAL PRODUCTS BY IN-SITU FIBEROPTIC UV MEASUREMENTS

The feasibility of using a fiber-optic UV/visible spectrograph for in situ dissolution testing of a pharmaceutical product containing two ac tive ingredients, sulfamethoxazole and trimethoprim, was demonstrated. Detailed dissolution profiles clearly showed that trimethoprim dissol ved rapidly, while sulfamethoxazole dissolved slowly. Multivariate cal ibration of the fiberoptic spectrograph was accomplished using full-ra nge spectra from 250 to 320 nm and principal component regress (PCR). Calibration mixtures were prepared from standard reference materials a ccording to a three-level, central composite factorial design. It was not necessary to include excipients in the calibration mixtures. The a ccuracy of the new in situ UV/visible method was compared to a standar d HPLC method and was limited to about +/-3% due to the high spectral similarity of the two active ingredients. The detailed dissolution pro files afforded by this new method may be an invaluable aid in the deve lopment of multicomponent, time-released drug products.