Tissue Distribution of Betulinic Acid Nanovesicles in Mice
OBJECTIVE To study the betulinic acid nanovesicle delivery system,and determine the distribution of the prepara-tion in mice.METHODS A physical characterization method of nanovesicles was established,focusing on the aspects of morphology,particle size,Zeta potential,etc.In the study of tissue distribution of betulinic acid nanovesicles in vivo,mice were injected through the tail vein,and the concentrations of betulinic acid in various tissues and plasma at different time points were determined by HPLC,and the targeting parameters were calculated.RESULTS Betulinic acid nanovesicles shape is spherical and uniformly dispersed.The par-ticle size is 140.51 nm,polymer dispersity index(PDI)is 22.58%,Zeta potential is-28.8 mV,encapsulation efficiency is 90.52%,drug loading is 8.30%.Compared with the injection group,the concentration of betulinic acid nanovesicles in the tissues and plasma of mice in the injection group was higher,the total area under the curre(AUC)increase 1.81 times,and the target evalua-tion index concentration ratio(Ce)of liver tissue is 3.51,relative tissue exposure(re)is 2.87,targeting efficiency(te)is 1.07.CONCLUSION The results show that the betulinic acid nanovesicles have small particle size,good stability,high encapsulation effi-ciency and drug loading,and meet the design requirements.The betulinic acid nanovesicle delivery system shows that the preparation of nanovesicles from betulinic acid can significantly improve the bioavailability of drugs and have obvious targeting to liver.