Paclitaxel palmitate-loaded anti-HER2 cationic immunoemulsion: pharmacokinetic and biodistribution study in healthy mice

The aim of this study was to evaluate the pharmacokinetic and biodistribution profile of paclitaxel palmitate (PCPL)-loaded anti-HER2 cationic immunoemulsion in healthy mice as compared to PCPL solution and PCPL-loaded cationic emulsion following intravenous (IV) injection. The observed density of the monoclonal antibody (MAb) conjugated to the cationic emulsion was found to be around 35 MAbs/droplet (70% coupling efficiency). Both PCPL-loaded cationic emulsion and immunoemulsion showed significant increases in t1/2, Cmax and AUC values as compared to the values of PCPL solution in mice. There was no significant difference in the t1/2 and Cmax values between PCPL-loaded cationic emulsion and PCPL-loaded immunoemulsion. However, the PCPL-loaded immunoemulsion concentrated much less in the liver and spleen than PCPL-loaded cationic emulsion. The pharmacokinetic behavior of the immunoemulsion was markedly different from the pharmacokinetic profile of the naked MAb showing that the MAb lost its intrinsic molecular pharmacokinetic properties following conjugation to the cationic emulsion.