Validated spectrophtometric method for determination of tamsulosin in bulk and pharmaceutical dosage forms.

In this study a sensitive, simple and accurate spectrophotometric method was suggested for determination of tamsulosin in bulk powder and pharmaceutical dosage form based on the formation of an ion-pair complex between the drug and bromocresol green in a buffer solution at pH 3.5. The formed yellow color complex was extracted with chloroform and measured at 415 nm. The optimum reaction conditions such as pH, reagent amount, extracting solvent and the stoichiometry of the ion-pair complex were investigated. Under the optimized conditions, the Beer's law was obeyed in the concentration range of 1-160 g/mL with acceptable correlation coefficient (r(2) > 0.9997) and precision (CV < 3%) and accuracy (error < 2%). The proposed method was successfully used for the determination of tamsulosin in pharmaceutical capsule with nosignificant interferences of excipients.