Distribution Of Baicalin Phospholipids Complex Into Brain Following Intranasal Administration

The subject studied three drug-loading systems of baicalin including phospholipid complex, liposomes andβ-CD inclusion.The results showed that the phospholipid complex composite rate is 97.23%, drug loading is 32.71% and the apparent permeability coefficient is [(82.97±15.13) 10-7] (cm·s-1), each of which is the highest of the three systems.The study on physical and chemical properties demonstrated that in water and N-octanol the dissolved amount of phospholipid complex is 4.56 and 70.17 times as much as baicalin separately.Therefore,it can be concluded that the solubility of baicalin has been obviously improved after forming phospholipid complex. It can be seen from stability experiments that phospholipid complex.has a certain sensitivity to temperature, humidity and time. Although the exterior color turns darker gradually, the content of baicalin didn't change. But it is stable to light. The preliminary study on the composite mechanism of Phospholipid complex through scanning electron microscope, infrared spectroscopy, quantum chemistry and so on indicated that phospholipid and baicalin formed a stable complex by intermolecular forces, in which there is no new compound produced by chemical combination.The study of nasal mucosa toxicity showed that phospholipid complex by intranasal administration has no obvious toxicity to the nasal mucosa of rats. Then we did the experiment of nasal mucosa absorption in vivo.The results manifested that in terms of saturated absorbance,there was no obvious difference between baicalin and phospholipid complex.but the absorbing speed of phospholipids complex is obvious faster than that of baicalin。Through making model of cerebral ischemia reperfusion injury of rat by suture method, we compared the effect of baicalin and phospholipid complex by intravenous injection and intranasal administration on water content of brain tissue and nerve function. The results demonstrated that:compared to baicalin through intravenous injection, the phosphplipid complex through intranasal administration could significantly improve the indices mentioned above. Nasal cilia removal experimental results showed that:phospholipids has a protective effect on the purge of nasal mucosa, and it could improve drug absorption by extending drugs'retention time in the nasal cavity.As can be seen from pharmacokinetics research, the AUC of phosphplipid complex through intranasal administration was remarkably higher than that of baicalin through intravenous injection,which manifested that the bioavailability of baicalin was significantly improved after forming phosphplipid complex.To sum up all the results of this subject, we can conclude that Baicalin is protective to the cerebral ischemia injury,and the pharmacological action gets stronger while forming phospholipids complex by intranasal administration. Conseqently, it provided a nice reaserch foundation for the treatment of brain disease and the improvement of effect, safty as well as administration change of TCM injections.