Chemometrics‐Empowered Optimization of a Reliable Reversed Phase–High Performance Liquid Chromatography Method for the Simultaneous Estimation of Erythromycin and Adapalene in Pharmaceutical Nanoformulation

ABSTRACT An innovative, simple, economical, and sensitive reversed phase–high performance liquid chromatography (RP–HPLC) chromatographic method for simultaneous analysis of erythromycin (ERY) and adapalene (ADP) in bulk and pharmaceutical nanoformulation was developed by analytical quality‐by‐design (AQbD) avenue. According to published research, there is no strategy that integrates RP–HPLC with AQbD for estimating ERY and ADP. The analysis was carried out with Box–Behnken design, which reduced trial runs and design points. Acetonitrile: orthophosphoric acid (OPA) (0.1% triethanolamine) in pH 6.2 water was used as the mobile phase. The ratio was set to 35:65 (v/v) at 0.8 mL/min flow rate to detect the analytes at 231 nm. As per the guidelines in International Conference on Harmonization Q1A (R2), the developed approach was validated. ERY and ADP regression coefficients ( r 2 ) were found to be 0.9998 and 0.9999, respectively, over 5–25 µg/mL range. Validation parameters comprising linearity, sensitivity, system suitability, precision, robustness, and accuracy were performed. To assess stability, the drugs were subjected to stress conditions (hydrolytic, oxidative, thermal, and photolytic), and drugs were most vulnerable to degrade in alkaline and oxidative conditions. A new technique successfully analyzed novel drug carriers loaded with ERY and ADP.