Modern kinetic spectrophotometric procedure for estimation of furosemide drug as bulk form and in pharmaceuticals preparations

A simple, rapid, sensitive, inexpensive and easy to perform kinetic spectrophotometric procedure for the investigation of trace quantities of the drug, furosemide (FRO), as bulk and in the pharmaceutical preparations, has been improved upon. The enhanced method was depended on the fashioning of the Schiff ‘s base by the reaction of the aldehyde group present in the 5-sulfo salicylaldehyde reagent, and the primary amino group present in furosemide. The latter acts as a ligand for the formation of an intense colored complex with Co(II) in an acidic medium, with maximum absorption at 608 nm. In the work, kinetic spectrophotometrics were established through the fixed time method. Moreover, Beer’s law was applied on the range of concentration between 5-100 ppm, while the molar absorptivity and the Sandell sensitivity were 3.9295×104 l.mol⁻¹cm⁻¹, 0.008 μg.cm⁻², respectively. The detection limit (LOD) was 2.133 µg/ml⁻¹, and LOQ was 1.105 µg/ml⁻¹. Ideal circumstances for all colour improvement were seen, and the suggested procedure has been effectively employed in investigating amounts of furosemide (FRO) in bulk forms and in pharmaceutical preparations (tablets, injection sample). Additives and general excipient materials did not affect the studied method. A statistical comparison between the results that were obtained from the reference method gave good agreement.