Study Of Biomaterials And Drug Delivery Systems Based On Degradable Phosphate Ester Cross-linked Bone

Phosphate esters play a dominant role in the physiology of cells and hence are essential to any organism. Most prominent roles for phosphate esters are the participation as a structural and functional element in DNA, RNA, and its monomeric building blocks, the occurrence as a posttranslational signal in proteins and as a head group in phospholipids. Recently, the material with the phosphate esters as the linked bone is of great interest in tissue engineer and drug delivery, due to the excellent degradability and biocompatibility.On the base of the advantages above, we designed and prepared a degradable thermoset elastomer with the phosphate bone as cross-link point. The cross-linked network was prepared by the curing of homogeneous mixture of diphosphoesters of polyethylene glycol (P-PEG-P) and diglycidyl ether of polyethylene glycol (E-PEG-E) at 50℃for 5 h. After analysis, we can get the conclusion (1) the preparation of P-PEG-P and E-PEG-E was simple with high yield and conversion ratio. (2) the preparation of cross-linked polymer was simple with short production period. (3)the property of cross-linked polymer depended on the molecular weight and the ratio of prepolymers. The highest Young modulus would be obtained when the molecular weight of prepolymers were small and the ratio of epoxy group and P-OH was equal to 1.5. (4) the obtained cross-linked polymer showed good degradable ability, low cytotoxicity and potential application in drug release.We also designed and prepared a drug release system with the phosphate ester bone as the linked bone which was obtained by the reaction of P-OH of drug and the epoxy group of liner polymer or inorganic material. The preliminary tests of ultraviolet and high performance liquid chromatography (HPLC) indicated the drug release system has the ability to controlled-release drug.