A New Stability-Indicating RP-HPLC Method for Simultaneous Quantification of Diacerein and Aceclofenac in Novel Nanoemulgel Formulation and Commercial Tablet Dosage Form in the Presence of their Major Degradation Products Using DoE Approach

Abstract The present study aimed to develop a simple, robust, sensitive and effective stability-indicating reversed-phase high-performance liquid chromatography method for simultaneous quantification of diacerein (DCN) and aceclofenac (ACE) in novel nanoemulgel formulation and commercial tablets in the presence of their main degradation product: rhein (RH) and diclofenac sodium (DLS), respectively. A fractional factorial design was used to screen the crucial independent factors, whereas a central composite design was used for the optimization of the chromatographic conditions. The separation was carried out on Phenomenex C18 column (5 μm, 250 × 4.6 mm), using a mobile phase consisting of phosphate buffer pH 3 (0.1% v/v orthophosphoric acid) and acetonitrile (40:60 v/v) at a flow rate of 1 mL/min with detection at 264 nm. The analytes were exposed to a variety of stress conditions, including heat, alkali, acid, oxidation, photochemical, humidity and hydrolysis. DCN, ACE, RH and DLS were found to have retention times of 4.32 ± 0.15, 5.77 ± 0.07, 8.28 ± 0.20 and 9.10 ± 0.18 min, respectively. The percent recovery for all four analytes was found to be between 98 and 102, and the procedure was discovered to be linear in the range of 0.1–64 μg/mL with R2 value > 0.999. The established method was validated as per ICH guidelines and successfully used to assay DCN and ACE in their combined marketed tablet dosage form and developed nanoemulgel formulation.