Improved solubility and pharmacokinetics of PEGylated liposomal honokiol and human plasma protein binding ability of honokiol.

PEGylated liposomal honokiol had been developed with the purpose of improving the solubility and pharmacokinetics compared with free honokiol. Human plasma protein binding ability of honokiol was also investigated. PEGylated liposomal honokiol was prepared by thin film evaporation-sonication method. Its mean particle size was 98.68 nm, mean zeta potential was -20.6 mV and encapsulation efficiency were 87.68±1.56%. The pharmacokinetics of PEGylated liposomal honokiol was studied after intravenous administration in Balb/c mice. There were significant differences of parameters T(1/2β) and AUC(0→∞) between them and liposome lengthened T(1/2β) and AUC(0→∞) values. The mean T(1/2β) value of PEGylated liposomal honokiol and free honokiol were 26.09 min and 13.46 min, respectively. The AUC(0→∞) ratio of PEGylated liposomal honokiol to free honokiol was about 1.85-fold (219.24 μg/mL min/118.68 μg/mL min) (P=0.000). Examination of protein binding ability showed that honokiol with 0.5, 8.0 and 20 μg/mL concentrations in human plasma achieved the percent of bound between 60% and 65%. The results suggested that PEGylated liposomal honokiol improved the solubility, increased the drug concentration in plasma, and withstanded the clearance. Besides, the percent of protein bound of honokiol in human plasma was between 60% and 65%.