QbD approach to method development, validation and degradation profiling of antifungal drugs by RP-HPLC

For the simultaneous estimation of Itraconazole (ITZ) and Terbinafine hydrochloride (TBF HCl) in tablet dosage form, a simple, novel, cost effective and rapid RP-HPLC method was developed. Method development becomes quick, accurate, sensitive, and robust by using quality by design (QbD). RP-HPLC was performed using a C18 (agilent, 4.6 x 250mm, 5μm particle size) column. Methanol and 0.05% OPA (pH 3.5) was used as mobile phase in 84:16 ratio. The analysis was conducted in gradient mode with a flow rate of 0.95mL/min. Detection wavelength was set at 270nm. Retention time for TBF and ITZ was at 2.93 and 6.96min, respectively. The accuracy, precision, repeatability, linearity, LOD, LOQ and robustness parameters have been validated as per the ICH Q2 (R1) guideline: Validation of analytical procedures-text and methodology. Values for LOD and LOQ were found to be 0.131 and 0.398μg/mL and 0.350 and 1.061μg/mL respectively for ITZ and TBF HCl. Thus, the technique can be employed for regular QC analysis of bulk ITZ and TBF HCl and their pharmaceutical formulations. Degradative stress conditions like acid, base, neutral, oxidation applied and degradations were studied.