Quantitative Analysis Of Cross-linked Dextran In Sodium Hyaluronate Hydrogel

Medical cross-linked sodium hyaluronate hydrogel is used for the repair of tissue defects and plastic surgery.Cross-linked dextran have served as the packing medium to improve the performance of cross-linked sodium hyaluronate hydrogel in stability and sustained-release.There are some rigorous requirements for medical products including the properties,identification,quantification and other items in pharmacopeia.However,so far no relevant reports about the quantity of cross-linked dexran have published.Therefore,it is significance to empolder a quantitative analysis method for theory and practical application.In this paper,the methods of high performance liquid chromatography(HPLC),UV-Vis spectrophotometry(UV-Vis),thermogravimetry(TG),pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)were applied to exploring the feasibility of quantifying cross-linked dextran.We developed a rapid analytical method by Py-GC/MS,which selecting the characteristic peaks of glycerol thermally decomposed from cross-linked dextran as the quantitative component.The reproducibility and the recoveries of cross-linked dextran were analyzed.Furthermore,the thermal stability,pyrolysis mechanism and kinetics of cross-linked dextran were studied.The results showed that: The hydrolysate of cross-linked dextran was so complex that it difficult to accurate quantitative analysis by HPLC or UV-Vis.The accuracy of the thermal analysis method were slightly insufficient to determinate real samples.The content of cross-linked dextran in medical hydrogel was analyzed by Py-GC/MS without sample pretreatment.A good linear relationship was observed between glycerol and cross-linked dextran in the range of 0.32 mg~1.14 mg,with more than 0.9998 of correlation coefficients at 600?.The recoveries of cross-linked dextran were 91.88%~102.94%,the relative deviation of result was 0.40%,and the relative standard deviation(RSD)was 5.52%(n=5).The characteristic initial decomposition temperature of cross-linked dextran in nitrogen was 311.1?,the termination decomposition temperature was 328.3?,and the activity energy of thermal decomposition was 70.84 kJ/mol.It may brought out several competitive reactions such as the lateral radical elimination,the retro-grade aldol condensation,the transglycosylation and the fracture at the alpha position of the ether bond.