RP-HPLC method for simultaneous determination of rosuvastatin and ezetimibe in novel synthesized lipid-polymer hybrid nanoparticles

Abstract Rosuvastatin and ezetimibe, each with distinct mechanisms of action, have a well-established use in hyperlipidemia treatment. The recent adoption of their fixed-dose combination therapy has gained significant attention due to its enhanced therapeutic efficacy in managing hyperlipidemia and improved patient convenience. However, both active pharmaceutical ingredients (APIs) face challenges related to low bioavailability and non-selective action, highlighting the need for delivery systems able to target and control their release at the site of action. To overcome these limitations, lipid-polymer hybrid nanoparticles (LPHNPs) have been developed, leveraging the combined advantages of lipid and polymer nanocarriers for improved API delivery. This study focuses on the development and validation of a simple reversed-phase high-performance liquid chromatography (RP-HPLC) method for the determination of rosuvastatin and ezetimibe in the developed LPHNPs, optimized to assess critical attributes of quality such as encapsulation efficiency (EE) and API loading capacity, which influence therapeutic outcomes. Chromatographic separation was achieved by using a Zorbax Eclipse Plus C18 column and a mobile phase of diluted formic acid and acetonitrile (55:45, V/V ) at a flow rate of 1.5 mL min −1 . Detection was performed at 240 nm. The method was validated according to ICH Q2(R2) guideline, demonstrating excellent linearity, accuracy, precision and robustness. The proposed method was used for the successful quantification of the EE and loading capacity of both APIs in LPHNPs, showing also potential for analysing their release profile by which valuable insights into their release mechanism and kinetics from the nanoparticle system could be obtained, and the stability of the designed delivery system as well, by providing effective assessment of API leakages from the LPHNPs over time, when kept at specific storage conditions.