Development of a Biorelevant In Vitro Release System and Level A In Vitro‐In Vivo Correlation for Doxorubicin Hydrochloride Liposome Injection via Flow‐Through Cell Method

ABSTRACT Doxorubicin hydrochloride liposome injection represents a complex nano‐drug delivery system with significant clinical advantages, yet its quality evaluation remains challenging. Traditional static release methods often fail to simulate the physiological environment, which leads to poor in vivo predictions. The flow‐through cell method provides distinct advantages by simulating hemodynamic characteristics and maintaining stable sink conditions. This study utilizes the flow‐through cell method to simulate the release process of doxorubicin hydrochloride liposomes and establishes a Level A in vitro‐in vivo correlation (IVIVC) based on the in vivo data of three commercial brands to develop a biorelevant in vitro release method. The in vivo cumulative release fraction is derived from the plasma concentration data of three commercial products using the fractional area (AUC) method for deconvolution, which serves as the target reference for the in vitro release profile. In vitro release experiments are conducted using a phosphate buffer containing 0.3% SDS and 15% artificial plasma as the release medium, which is optimized through single‐factor analysis and an L 9 (3 4 ) orthogonal experimental design. The experimental setup employs a dialysis membrane with a 300 KDa molecular weight cutoff and a flow rate of 4 mL/min. High‐performance liquid chromatography (HPLC) determines the concentration of the released drug to calculate the in vitro cumulative release fraction. A Level A IVIVC model is established between the cumulative in vitro and in vivo release fractions of doxorubicin hydrochloride liposome injection, which is subsequently confirmed through internal validation. The IVIVC model demonstrates robust predictive capability, and the developed in vitro release method exhibits high sensitivity in distinguishing the release characteristics of products from different manufacturers. This study provides a scientific reference for the in vitro‐in vivo correlation and quality evaluation of long‐acting injections.