The Study Of The Thermosensitive Polymer In Situ Gelation As Liquid Embolic Material

Interventional radiology is an interdisciplinary subject in medical imaging and clinical therapy. It is based on medical imaging, and under the guidance of imaging equipment, uses micro catheter or other interventional devices to diagnose disease or treat diseases. Interventional embolization is an important basic technique in interventional radiology, by which the embolic material is injected into the diseased organs through the micro catheter with the help of medical imaging to treat the tumor or vascular disease.At present, there are many kinds of embolic materials, such as spring coil, detachable balloon, iodized oil, PVA granule, kelp micro gelation, ONYX, etc. Different embolization materials can be adapted to different positions and different nature of the lesion. In view of the present situation and the existing problems in the research of embolization materials, the in situ gelation thermosensitive copolymer for liquid embolic materials was designed and synthesized by using N-isopropylacrylamide as a main monomer in this dissertation, and its properties were investigated. Main research work is as following.1. Monomer and polymer were synthesized and characterized, including (1) to exploit N-isopropylacrylamide (NIP) purification method; (2) to synthesize copolymer poly(NIP-co-BMA) by copolymerization of NIP and butyl methacrylate(BMA), and investigate the effects of reaction time, reaction temperature, monomer ratio, initiator amount on the properties of the product; and (3) to characterize the structure of poly(NIP-co-BMA) by IR and1HNMR, and investigate the effects of Iohexol and salt solutions on the properties of aqueous solution of polymer, especially the low critical solution temperature and the phase transition time.2. Embolic agent was prepared by dissolving poly(NIP-co-BMA) into water. The optimal monomer ratio and the optimal concentration of the embolic agent were determined by the experiment in vitro. The best push speed is also selected, which can make the model in vitro can not only embolism completely, and will not cause false bolt. The dosage of the embolic agent needed in the model was recorded.3. The storage stability of the thermosensitive polymer in situ gelation as medical liquid embolic material was studied. Properties of the embolic materials were detected, mainly including low critical solution temperature, phase change time, viscosity, pH, heavy metal content, etc., which provided reliable original data for clinical operation.Through experiments, the best polymerization conditions and the preparation methods of solution were obtained. The thermosensitive copolymer in situ gelation as liquid embolic materials has the following advantages:(1) the embolic material is liquid, and convenient to inject; (2) the embolic material is dissolved in water for injection, no using organic solvent; (3) the embolic material has the characteristics of temperature sensitivity. When the temperature reaches 37.0 degrees Celsius, the embolic materials have a phase transition, and the blood vessel could be embolized.- The thermosensitive polymer in situ gelation as medical liquid embolic material is a kind of non-toxic material with temperature sensitivity. Its physical properties and the chemical properties of the materials are in accord with the national standard and the requirement of Chinese Pharmacopoeia.It will have good clinical application prospect.