Study On Absorption Of Hyaluronic Acid After Oral Administration And Its Mechanism

Hyaluronic acid (HA) is a high molecular mass linear glycosaminoglycan consisting of repeating disaccharide units ofβ-(1,4)-D-glucuronic acid-β-(1,3)-N-acetyl- D-glucosamine. It is found ubiquitously in the body, and especially abundant in soft tissues (e.g. synovial fluid, vitreous humor of the eye, skin). Since the turnover rate for HA is remarkably high and reduction of HA can cause arthritis, eyes blurred and wrinkles of the skin, people suppose that taking exogenous HA orally should supply the shortage of the endogenous HA which exists in skin and other tissues and prevents the aging. Hence, various health foods and drugs containing HA are focused on gradually. The effect of HA after oral administration has got the approbation, but whether or not HA can be absorbed, if it can, and how mechanism is, is still unclear now. Unlabelled or isotope-labelled HA and relevant monosaccharides were taken orally to study the absorption of HA and its mechanism. The aim of this article is to provide a valuable scientific basis for the development of health foods and drugs containing HA. The main investigations and conclusions are as follows:1. Flowing steam was used to degradate high relative molecular mass (Mr) HA. And special low Mr distribution range of HA was prepared for studying the absorption of HA after oral administration. The mechanism of thermal degradation of HA may be chain-breaking or chain-shortening which induces the Mr reduction of HA.2. The concentrations of HA in rat serum after taking orally a single dose of various Mr HA were determined by radioimmunoassay. The ? AUC0-12 h of serum HA concentration-time curve was calculated by trapezoidal integration and used as an evaluation index. It was discovered that the serum HA levels of each HA group appeared an absorptive peak. The results suggested that HA should be absorbed after oral administration. The influence of Mr and dosage on absorption of HA was also investigated. It was found that the optimal Mr and dosage were about 100×104 and 20...