Background: In view of the current FDA standardization and product quality control criteria,
Quality by design approach for analytical methods is gaining importance to develop a robust analytical
method. A new Quality by Design approach by RP-HPLC was developed and validated for the
quantification and purification of Tadalafil hydrochloride and its tablet formulations.
Objective: The objective of the study was to develop and validate a simple, robust, and accurate method
by QbD approach for the detection of Tadalafil hydrochloride and its degradation products in bulk
drug and tablet formulation.
Methods: The chromatographic separation was performed on JASCO Crest Pack RPC18 column
(250mm×4.6mm, 5μm) with mobile phase A consisting of a mixture of Acetonitrile: Methanol (40:20
v/v); and mobile phase B: 0.01M Ammonium acetate in water pH adjusted to 3.50± 0.05 with glacial
acetic acid with 1.0ml/min flow rate at 285nm. Box-Behnken's three-level, 3-factorial design was employed
to create and analyze a "Design Space" (DoE). This design was statistically analyzed by ANOVA,
counter-plot, and 3D response surfaces plots, which demonstrated that the model was statistically
significant. The developed method was validated as per the ICH guidelines Q2 (R1).
Results and Discussion: The tadalafil hydrochloride showed good regression (R2>0.9995) within tested
ranges, and the percent recovery was found to be 98% in the marketed formulation.
Conclusion: The method was found to be highly specific without the interference of impurities and
degradation products of tadalafil hydrochloride. For quantification and routine quality control of tadalafil
and its marketed formulation, the stability-indicating the RP-HPLC method could, thus, be extended.