Tamsulosin dissolution from pharmaceutical dosage forms using an automated HPLC system

A novel, rapid, accurate, and sensitive high-performance liquid chromatographic assay was developed to determine tamsulosin (TAM) in pharmaceutical dosage forms and to follow its dissolution pattern. An efficient separation of TAM was performed using stainless steel Supelcosil LC-18 column (25 cm x 4.6 mm; 5 pm particle size) preceded by a Sentry guard column. The mobile phase consisted of an aqueous solution containing acetonitrile 70% (pH 3.4 adjusted with glacial acetic acid) and delivered at a flow rate of 0.75 mL/min. The compound of interest was detected using photodiode array detector at 225 nm. Under these conditions, the retention time for TAM was 6.1 +/- 0.2 min. The detector response was linear for TAM in alkaline solution (r > 0.9975) in the range of 0.025-1.00 mug/mL. The detection and the quantification limits for TAM were 0.015 and 0.025 mug/mL, respectively. No interferences were observed from the capsule's excipients. The drug content in each capsule ranged from 99 to 101%. The dissolution study of OMNIC(R) capsules revealed that TAM in USP media (pH 1.2) showed no dissolution up to 12 h. However, a first order release kinetic, with dissolution T-50% of about 2 h, was observed in USP media (pH 7.4).