Sensitive Bromatometric Determination of Finasteride in Pharmaceuticals Based on Complex-Formation Reactions

The study described two highly sensitive spectrophotometric methods for determining finasteride in its pure and tablet forms. Method A involved bromination of finasteride, followed by treatment with iron (II) and complexation with thiocyanate, measured at 470 nm, showing a linear decrease in absorbance with increasing finasteride concentration. Method B used a similar bromination process, with iron (II) complexed with orthophenanthroline at a raised pH, measured at 510 nm, showing a linear increase in absorbance. Both methods adhered to Beer’s law within specified concentration ranges and demonstrated high accuracy and precision according to ICH guidelines. The methods were successfully applied to tablet analysis, with results aligning closely with label claims and a reference method, unaffected by excipients.