The Comparison Of Gel Properties Between Heparin-poloxamer 188 And Heparin-poloxamer 407

Objectives : To synthesize the copolymer of HP 188 and HP407,study the characterization and physical properties of this two copolymers,and to compare the gel temperature between HP 188 and HP407.The research was also designed to evaluate which hydrogel was more suitable for vascular anastomosis.Methods:Part I: for the preparation of the material,using poloxamer 188,poloxamer407 and ordinary heparin sodium to synthesize the copolymer of HP with the method of EDC / NHS.The characterization of those two kinds of copolymers could be detected by the mothods of infrared spectroscopy and magnetic resonance spectroscopy.The content of heparin in the copolymer could be determined by the method of toluidine blue staining,which determines whether the material was successfully synthesized.Part II is the comparison of those two materials,which is to prepare different concentrations of HP solution and to compare the two copolymers’ gel properties.With the method of differential scanning calorimetry(DSC),using the comprehensive thermal analysis system to measure the gel temperature of the different concentrations of the copolymer,we can study the relationship between gel properties and concentration.Results:In this experiment,HP 188 and HP407 were successfully synthesized.Through this experiment,it can be observed that the too high concentration(40%)of the copolymer is difficult to prepare,but too low concentration(10%)does not occur gel reaction,so the appropriate concentration of HP 188 and HP407 is between20%-35%.By measuring the gel temperature of the two copolymers,it was found that the gel temperature was related to the concentration,the higher concentration may with the lower gel temperature.The gel temperatures of 20%,30% and 35%HP188 were about 44℃,35℃ and 33℃,respectively.The gel temperatures of 20%,30%and 35%HP407 were about 31℃,30℃ and 30℃.Hence,the gel temperature of HP407 was lower than that of HP 188 at the same concentration.After reached the gel temperature,HP407 had higher thermal stability than HP 188.And compared 35%HP407 with 20%,30%HP407,it was found that the gel temperature were little difference,but the thermal stability of 35% is better.Conclusions:When the HP407 hydrogel at a concentration of 20%-35%,the gel temperature slightly higher than room temperature,thermal stability is good,and the preparation is easier,taking into account,HP407 may be more suitable for HP 188 for vascular anastomosis of the thermo-sensitive materials,and the most suitable concentration of HP407 is 35%.However,before HP is applied to human surgery,a lot of research is needed,such as the biological toxicity of the material and its absorption,excretion and other issues.