Optimisation and validation of a rapid RP-HPLC method for budesonide quantification from polymeric nanoparticles with application to stability and drug release studies

A rapid and reliable reversed-phase high-performance liquid chromatography (RP-HPLC) method for quantifying budesonide encapsulated in poly(lactic-co-glycolic acid) (PLGA)-based, layer-by-layer (LbL) coated nanoparticles is developed and validated in this study. Optimization using response surface methodology (RSM) with a central composite design (CCD) identified acetonitrile: water (80:20, v/v) as the optimal mobile phase, enabling efficient separation within 5 minutes at a flow rate of 0.34 mL/min and detection at 244 nm. Consistent with ICH Q2(R2) guidelines, the method demonstrates excellent linearity (R² > 0.999), precision (% RSD < 2 %), accuracy, specificity, and sensitivity (LOD: 0.04 µg/mL; LOQ: 1.2 µg/mL). The validated method was applied in comprehensive forced degradation studies under diverse stress conditions, including acidic, alkaline, oxidative, thermal, photolytic, and photostatic environments. The LbL coating offered significant protection for budesonide, resulting in less than 20 % degradation under thermal and photostatic stress. In contrast, degradation exceeded 75 % when exposed to alkaline and oxidative conditions, particularly in hydrated environments. These findings underscore the critical importance of nanoparticle design and environmental conditions in ensuring drug stability. Furthermore, in vitro release studies demonstrated a sustained release profile (20.6 % over 48 h), indicating potential for targeted colonic drug delivery. Overall, this study is the first to establish a validated HPLC method for drug-loaded, LbL-coated nanoparticles, providing a robust analytical platform for characterizing and evaluating the stability of nanoparticle-based drug delivery systems for inflammatory bowel disease, facilitating their clinical translation.