Fluorescence spectral behaviour of amlodipine besylate and dobutamine hydrochloride and their determination in dosage forms and spiked plasma

ABSTRACT

The present work describes sensitive, simple and validated fluorimetric methods for the determination of Amlodipine besylate [AM] and Dobutamine Hydrochloride [DO]. The methods depend on measurement of native fluorescence intensity of both drugs at lombda emission 450nm, and 310nm using lombda excitation 360nm and 272nm for both drugs. The fluorescence spectral properties of AM and DO was also achieved in presence of different surfactants, beta-cyclodextrin and some metal ions. Quantum yield, formation constant [K] and free energy changes [delta G] values were calculated, for all the suggested methods under the optimum condition and experimental parameters. Linear relationships and good correlation coefficients [0.9995-0.9999] were found between fluorescence intensity, and the concentration ranges of the investigated drugs. No interference was observed when the methods were applied in the presence of co- administrated and common drugs. Moreover the methods can be used as stability indicating methods for AM. The results obtained were statistically comparable with those obtained by official methods. The proposed methods were successfully applied to the determination of AM and DO in bulk powder, dosage forms, and spiked human plasma. The validity of the methods was assessed according to USP guidelines and also by applying the standard addition technique