Experimental design approach to optimize stability indicating liquid chromatography method for the determination of naftopidil in its bulk and tablet dosage form

Objective: To develop and validated a new stability indicating reverse phase high performance liquid chromatography (RPHPLC) method for analysis of naftopidil (NAF), both as a bulk drug and in formulation. Method: The separation was achieved using a C18 GRACE column (250 mm × 4.6 mm i.d., 5 μm particle size) and gradient mobile phase system consisting of (A) 10 mM of ammonium acetate buffer pH adjusted to 4.0 with glacial acetic acid and (B) acetonitrile. The fl ow rate was 1.0 mL/ min with UV detection at 284 nm. NAF was subjected to stress conditions like hydrolysis (acid, alkali and neutral degradation), oxidation, photolytic and thermal decomposition. The linearity of the proposed method was investigated in the range of 10-150 μg/mL. Application of design of experiments for the robustness study method was carried out, where in fi ve factors was selected: pH of mobile phase, fl ow rate, strength of the buffer and column temperature. These factors were examined using JMP@ (SAS Institute) software. Result: The analytical method for NAF was developed and validated at the linearity range of 10-150 μg/mL. The LOD and LOQ were 0.6 and 2.04, respectively and accuracy of analysis was 100.5-101.1%. Conclusion: A robuststabilityindicating HPLC assay method was developed using DOE, for the quantitation of NAF in its bulk and tablet dosage forms