Dutasteride

A simple, rapid, sensitive, accurate, precise spectrophotometric method has been developed for the estimation of Tamsulosin in the presence of Dutasteride  in pharmaceutical formulations. During the course of study, it is observed that acidic solution of the drug formed colored ion-association complexes with Bromo Thymol Blue (BTB) which is soluble in methanol. This property of the drug was followed for the development of spectrophotometric method for analysis of drug. The complex of Tamsulosin in the presence of Dutasteride with Bromo Thymol Blue showed ?max at 430 nm. The linearity range for Tamsulosin in the presence of Dutasteride was 10 µg/ml to 250 µg/ml. Recovery studies gave satisfactory results indicating that none of common additives and excipients interfere the assay method. The molar absorptivity and the sandell sensitivity of the method are found to be 6.6123×104 lit/mole/cm and 0.0067 µg/ml/cm2 respectively. 

The objective of the present research work is to develop a gradient, reversed-phase liquid chromatographic (RP-UPLC) method for the determination of Dutasteride in pharmaceutical bulk drugs for assay and its related impurities. The chromatographic separation was achieved on a Waters ACQUITY TM UPLC C8 Column (100mm×2.1mm, 1.7µm),. The isocratic LC method employs mixture of buffer and Acetonitrile in the ratio of (50:50 v/v) solutions as mobile phase. The buffer solution contains 1.0mM potassium di hydrogen orthophosphate pH adjusted to 5.0 with dil.Potassium hydroxide solution (Buffer) .The flow rate was 0.4 ml/min and the detection wavelength was 210 nm. In the developed UPLC method, the resolution between Dutasteride and its potential impurities, namely Imp-1, Imp-2 and Imp-3 was found to be greater than 4.0. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in Acidic medium and mild degradation observed in base hydrolysis stress conditions. Degradation product formed during acidic hydrolysis was found to be Unknown impurity. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed RP-UPLC method was validated with respect to linearity, accuracy, precision and robustness. The developed method was found to be linear in the range of 2.5-15µg/mL with correlation coefficient of 0.999 for assay procedures and found to be linear in the range of 0.05-3µg/mL with correlation coefficient of 0.999 for related impurities