Preparation of bovine serum albumin-γ-cyclodextrin conjugate and its solubilization and delivery performance for paclitaxel

In this study, bovine serum albumin-γ-cyclodextrin (BSA-CD) conjugate was prepared to explore its solubilization effect on Paclitaxel (PTX) and the underlying mechanism. The aqueous solubility studies revealed that when 0.1 mM BSA-CD conjugate was complexed with 4 mM PTX, the maximum aqueous solubility of PTX reached 34 mM, which was approximately 5-fold higher than that of the clinical formulation Abraxane™, with drug loading capacity increased by about 2.8-fold. In vitro release studies demonstrated that the inclusion complex exhibited a cumulative PTX release of approximately 14% over 72 h at pH 7.4 and approximately 23% at pH 5.5, indicating a pH-responsive release profile. MTT assays confirmed that the BSA-CD carrier was non-cytotoxic, and the inclusion complex at the concentration of 10 μM exhibited superior cytotoxicity against melanoma B16F10 cells compared to free PTX and Abraxane™. This study confirms that the BSA-CD conjugate, through the synergistic “dual encapsulation” effect of the BSA hydrophobic pocket and the γ-CD hydrophobic cavity combined with a moderately aggregated state modulated by specific ionic strength, significantly enhances the aqueous solubility and delivery efficiency of PTX, providing a novel and efficient carrier as well as new insights for the formulation optimization of hydrophobic anticancer drugs.