Determination of finasteride, indapamide and tiemonium methyl sulphate using surface plasmon resonance band of silver nanoparticles

A simple and sensitive method was developed for spectrophotometric determination of finasteride, indapamide and tiemonium methylsulfate in their pure form and in their pharmaceutical formulations. It was found that the studied drugs have the ability to reduce silver nitrate to silver nanoparticles (AgNPs) in the presence of sodium citrate as a stabilizing agent. Silver nanoparticles (AgNPs) produce a very intense surface plasmon resonance peak at 423 nm that allows the quantitative determination of the studied drugs. The calibration curves were linear with concentrations range of 0.50–5.00, 0.50-5.00 and 0.30-2.00 μg/mL for finasteride, indapamide and tiemonium methylsulfate, respectively. The proposed method was successfully applied to the determination of the studied drugs in their pharmaceutical formulations. Furthermore, content uniformity testing of the studied pharmaceutical tablets was also conducted.