Study on the bioavailability of baicalin-phospholipid complex by using HPLC.

A complex of baicalin with soy phospholipid was prepared to improve the bioabsorption of baicalin. A simple and sensitive HPLC method was developed for baicalin determination in rat plasma. It was shown that its plasma concentration reached a peak of 0.42 microgram/mL 5.3 h after oral administration, 600 mg/kg. However, after intake of its phospholipid complex, a peak of 0.90-microgram/mL occurred at a later time, 6.1 h. The elimination of the complex tended to be slower than that of the free drug. There was a significant difference in the mean area under the concentration-time curves (AUC) between the free drug and the complex (p < 0.01).