Assay of new combination of tamsulosin and tadalafil using synchronous spectrofluorimetric method coupled with...

A fixed-dose combination therapy of tamsulosin andtadalafilis now available for treatmentof lower urinary tract symptoms associated with benign prostatic hyperplasia. The decrease in sexual performance which is a side-effect of tamsulosin can be compensated by using tadalafil. This study is the first to develop and optimize a synchronous spectrofluorimetric method coupled with derivative and derivative ratio mathematical tools for the determination of tamsulosin andtadalafil in their newly released dosage form. The method successed in quantification of tadalafil by measuring the second-order derivative synchronous spectrofluorimetric amplitude at 278 nm (corresponding to zero-crossing of tamsulosin) using Δƛ=11 nm. On the other hand, first derivative ratio synchronous spectrofluorimetric peak amplitude was measured at 260 nm for determination of tamsulosin, using Δƛ=15 nm and divisor concentration of 0.1 µg mL^-1. The method validation was performed using ICH guidelines. The linear responses of tamsulosin andtadalafil were from 0.04 to 0.5 and 0.05-0.5 µg mL^-1, respectively. High sensitivity was achieved as represented by slope values of 0.32 and 608.4 for tamsulosin andtadalafil, respectively. The method is sensitive enough to detect concentration as low as 0.024 for both drugs. The proposed integrated spectrofluorimetric method showed good simplicity, selectivity and greenness. It can be successfully applied for analysis of both drugs in dosage form.