SIMULTANEOUS DETERMINATION OF TADALAFIL AND ITS RELATED COMPOUNDS IN PHARMACEUTICAL DOSAGE FORMS BY UPLC

Abstract

A stability indicating UPLC method was developed and validated for simultaneous determination of tadalafil and its impurities in tablets. The chromatographic separation was performed on Acquity HSS T3 column (1.8 µm, 2.1 mm × 150 mm) using gradient conditions with methanol and ammonium acetate buffer (0.02 M; pH 4.0 adjusted with acetic acid) at a flow rate of 0.35 mL/min. UV detection was performed at 262 nm. Total run time was 10 min for performing the analysis in which the main compound and five known and other unknown impurities were separated. The method was suitably validated with respect to linearity, limit of detection, limit of quantification, accuracy, precision, and selectivity. The calibration curves obtained for the five impurities were linear over the range 0.112 to 1.96 µg/mL. The relative standard deviations of intra- and inter-day experiments were less than 1.5%. The detection limits ranged from 0.039 to 0.040 µg/mL depending on the impurity.

Keywords:

• degradant impurities
• method validation
• related compounds
• stability indicating
• tadalafil
• UPLC

ACKNOWLEDGMENT

The author would like to thank Management of Dr. Reddy's Laboratories for providing the facility to perform this research.

Notes

^a Based on signal to noise (S/n) ratio.

^b Determined on six levels.

^c Y is the peak area of each impurity, x the mass concentration in µgml⁻¹, and S.D. ^c and S.D. ^d the Standard deviation of slop (a) and intercept (b), respectively.

^e Determined on duplicate injections.

^f Average of six determinations.

^g Determined on six values.

^a Determined with triplicate at each level.

^a Determined with triplicate at each level.

^a Numbers in parentheses represent percentage area against respective standard.