Automated flow injection fluorimetric determination and dissolution studies of bumetanide in pharmaceuticals

A novel, sensitive and automated flow injection (FI) method with fluorimetric detection based on the strong fluorescence in alkaline medium has been developed for the assay, content uniformity and automated dissolution studies of bumetanide in pharmaceutical dosage forms. A fully automated FIA system controlled by home-made software (FIA-MOD 2.2.) was used for optimising the chemical and manifold parameters and running of routine measurements. The optimum excitation wavelength for bumetanide is 314 nm and emission wavelength greater than or equal to 370 nm. The measurement throughput is 60h(-1) using 110 mul sample volume. The useful concentration range is 0.05-10.0 mug ml(-1) with an R.S.D. of 0.46% (n = 3; c = 1.0 mug ml(-1)). Common excipients for tablets and injections were found not interfering. The assay results of two commercial drug formulations (tablets and injections) obtained with the proposed method agreed well with those obtained with the current USP method (HPLC-UV detection). Using this automated method the complete dissolution profile of bumetanide tablets was obtained. (C) 2001 Elsevier Science B,V. All rights reserved.