Preparation Of Hyaluronic Acid-phospholipid Complex And Its Absorption After Oral Administration

In order to improve the oral bioavailability of hyaluronic acid (HA) and educe its functions of aesthetic and health care, a complex of HA-PL was prepared with egg lecithin (PL) as absorption enhancer. The preparation technology was established after studying preparative methods, relative molecular mass (Mr) of HA, sonication time, reaction time, the proportion of HA and PL, HA concentration, and so on. The suspension of PL was prepared by the method of film dispersion and sonication firstly. Then the suspension of PL was mixed with HA solution and the complex was obtained after stirring under a constant temperature for a definite time. The preparation technology was as follows: the Mr of HA of 99.2×10~4, the concentration of HA of 6 mg/ml, HA : PL 1:3 (w/w), the time of sonication of 10 min and the incubation time of 6 h under 37℃.The differences between physico-chemical properties of complex and that of HA were obvious. (1) Microscopical appearances: It was found that the vesicles of PL gathered together around HA by transmission electron microscope and atomic force microscope. This phenomenon illustrated that PL combined with HA by some acting force. (2) Thermochemical properties: The results of differential scanning calorimetry demonstrated that the endothermic peak by phase transition and the exothermic peak by oxygenolysis of PL in the complex were both disappeared. But the thermochemical property of HA had no obvious changes. It revealed that HA could protect PL and make the sensibility of PL to temperature lower. (3) Infrared absorption: The results...