Development and Validation of Stability Indicating Derivative Spectrophotometric Methods for Determination of Duloxetine Hydrochloride

Aim: The aim of the present investigation was to develop and validate a rapid, sensitive, cost effective and reproducible stability indicating derivative spectrophotometric method for the estimation of duloxetine HCl in bulk and in formulations.
Methodology: First order derivative spectrophotometric methods were developed for duloxetine HCl employing peak-zero (P-0) and peak-peak (P-P) techniques and their stability indicating potential was assessed in force degraded solutions. The methods were validated with respect to linearity, accuracy, precision and robustness.
Results: Linearity was observed in the concentration range 5 μg/mL-90 μg/mL with an excellent correlation coefficient (r2) of 0.999. The limits of assay detection values were found to range from 0.33-0.41 μg/mL and quantitation limits ranged from 1.01-1.24 μg/mL for the proposed methods. The proposed method was applicable to the determination of the drug in capsules and the percentage recovery was found to be 99.68±0.95%.
Conclusion: The developed methods were successfully validated and applied to the determination of duloxetine HCl in bulk and pharmaceutical formulations without any interference from common excipients. Satisfactory recovery in force degraded solutions suggests the stability indicating nature of the assay.