聚对苯二甲酸丁二酯-聚四亚甲基多嵌段共聚物结构及其生物性质

The Structure of PBT-PTMG Block Copolymer and its some Biological Properties

本文研究了PBT-PTMG多嵌段共聚物的相分离结构、血液相容性、膜材料对尿毒物质的渗透能力以及释放药物的特性等,进而对共聚物的结构与其生物学性能间的关系予以初步的讨论。

A new thermoplastic elastomerspoly (tetramethylene terephthalate) -poly (tetramethylene glycol) (PBT-PTMG) multiblock copolymer was developed in the seventies. The microphase domain formed from crystalline polyester hard segment plays a role in physical crosslinking. Simultaneously, polyether soft segmentforms amorphous elastic field. This elastomer has been extensively used as a rubber with good mechanical properties. Refined PBT-PTMG is smooth and not irritating to human tissue, So as a biomaterial it has been investigated. The relationships between the microphase separated structure of PBT-PTMG and some biomedical behaviour, for example, blood compatibility, Permeadility and drug delivery etc, have been studied in this paper. A) Crystalline-Amorphous microphase separated featureThe microphase separated structures of PBT-PTMG multiblock copoly -mer are shown in Fig. 1When hard/soft segment ratio of PBT-PTMG block copolymers equals to 20/80, 30/70 in weight, The size of amorphous field of polyether is about 2000A and 1300A respectively shown in Fig. 1. (Black field: polyester crystalline, White field. polyether amorphous.). The crystalization is increased with increasing of hard segment content in PBTPTMG. The result cart be seen in Xray diffraction. B) Adsorptions of uric poison materialsAdsorptions of creatinine, uric acid and VB on EMSAC (Encapsulated Microspheric Activated Carbon).With refined PBT-PTMG block copolymers and percentage of clearing is shown in table.The domain.s of amorphous structure of PBT-PTMG block copolymers have favour for water soluble materials to pass.C) Drug deliveryAnticancer drug Mitomycin G encapsulated by PBT-PTMG block copolymers with different hard/soft segment ratio has delivered in simulation solution(PH=7. 4: buffer solution). The results have very important value.The delivery speed of drug decreases with increasing of hard segment and is larger at starting period for each sample. After that sustained delivery reaches a constant rate (0.09--0.13.%/min). In conclusion: The rate and amount of Mitomycin C delivery can be controlled by adjesting the hard/soft segment ratio.