Pharmacokinetics Research On Bletillan Injections

Bletillan was a kind of heteropolysaccharide composed of mannose and glucose which could be obtained from Bletilla striata. It was a novel biodegradable polymers with some pharmacological activities such as anti-ulcer, anti-gastrointestinal bleeding, intestinal adhesion prevention. Bletillan injection had been primarily developed by acid hydrolysis and studied as plasma substitute in preclinical trials in China with satisfied effects. In this paper, pharmacokinetics research of three kinds of bletillan injections with different molecular weights (BT40, BT70 and BT110; bletillan molecular weights were 39 kD, 73 kD and 90 kD, respectively.) were undertaken, and their potencies as plasma substitutes or novel drug delivery materials were evaluatied accordingly.Determination of monosaccharides of bletillan was first established by hydrophilic interaction chromatography - evaporative light scattering detection (HILIC-ELSD) method, which could be used for the quantitative determination and quality control of bletillan materials and their injections.The pharmacokinetics profiles of bletillan injections (BT40, BT70, BT100) in rabbits were studied by intravenous administrations. A HILIC-ELSD method was developed and validated for the determination of BT40 injection in rabbit plasma, the procedure of plasma sample was successful established either. The pharmacokinetics data of bletillan injections fit with three-compartment model, with their t 1/2βvalues to be 5.41 h(BT40),8.28 h(BT70),13.20 h(BT100), respectively. In the statistical moment model, their MRT0-T[n] values was 4.17 h(BT40),8.51 h(BT70),14.99 h(BT100) respectively, and their MRT0-∞values was 5.92 h(BT40),10.07 h(BT70),20.37 h(BT100), respectively. The results indicated that half time of bletillan injections expanded in accordance with their improved molecular weight, which could meet different medical therapy needs.Hemocompatibility of bletillan injections (BT40 and BT70) were studied by hemolysis tests and plasma stability tests. Hemolysis tests in rabbit blood erythrocytes gave negative results, no degradations of bletillans were observed by plasma incubation tests. The results showed good hemocompatibility of BT40 and BT70.