Simultaneous determination of metolazone and losartan in their combined tablets using synchronous fluorescence spectroscopy

: Synchronous spectrofluorimetry is utilized to carry out a rapid, sensitive and reliable method for determination of the binary mixture of metolazone (MTL) and losartan potassium (LSP). Under optimized experimental conditions, the synchronized fluorescence spectra of the two drugs were measured at Δλ = 80 nm in acidic methanolic solution and intensities were recorded at 260 nm for MTL and 335 nm for LSP. Linear correlation between fluorescence intensity and concentration were obtained through the ranges 0.02-0.2 μg/mL and 0.2-2.0 μg/mL for MTL and LSP, respectively. Limits of detection were 3.02 and 0.12 ng/mL, whereas limits of quantification were 9.16 and 0.35 ng/mL for MTL and LSP, respectively. The designated procedure was easily and successfully adopted to determine the two compounds in their single, as well as in co-formulated, tablets and the results showed high precision and accuracy without any significant interference from common tablet excipients. A comparison of the obtained results with a published reference method was carried out and both showed good agreement with respect to accuracy and precision.