Preparation Of Water Dispersible Drug-load Polycaproluctone Nanoparticles And The Slow-release Of Its Coating

Along with the increasingly extensive use of stent,the surface drug coating of the stent began to get the attention of people.Generally,if we just coat the drug on the stent surface,these drug's half life in the presence of the stent is very short.This will result in a short time of drug action,low utilization rate of drug and toxic side effects.While put the drug and the biodegradable polymers dissolved in a common organic solvent and then coat them on the surface of the stent so that they can form a drug-biodegradable polymer sustained release coating.And it can greatly increased the half life of the drug.It first introduce desolvation method to synthesis of rapamycin-loaded water dispersible-polycaprolatone nanoparticles and synthesis of paclitaxel-loaded water dispersible polycaprolatone nanoparticles.The tradition emulsification desolvation method can not synthetic drug-load nanoparticles that can stay stable in aquecus phase.This article provide the method that synthesis of nanoparticles have solved the problem that using biodegradable polymer or random copolymer prepared drug-loaded nanoparticles that having a stable hydrophilic surface layer.Using this method synthetic rapamycin-loaded polycaprolatone nanoparticles and synthesis of paclitaxel-loaded polycaprolatone nanoparticles can be stable in water.So that we can use it as the drug coating of the body stents.By varying the reaction temperature?mixing method?reaction time?drug dosage?dialysis speed?initial volume of watr to study in which condition the nature of the microspheres are best.The results show that the best reaction temperature is 30?and the reaction time should be 60 min.Also the best dialysis nanosphere dispersion liquid is that it should fully immersed in deionized water.When ImL water dispersionthe drug-loaded polycaprolatone nanoparticles titrate in the initial water volume of lOmL,the obtained microspheres encapsulating have the highest rate.It introduced a HPLC method for the determination of encapsulation efficiency of rapamycin-loaded and paclitaxel-loaded polycaprolatone nanoporticles.Through test we find the specific peak position of the rapamycin and paclitaxel and their mobile phase's condition.Finally we get the way of free rapamycin and paclitaxel separated from the drug-loaded nanoparticles,the best extraction time is 2h and 1.5 h and the calibration of the rapamycin curve in the range of 5.0^50 ?g/ml and the calibration of the paclitaxel curve in the range of 5.0^50 ? g/mlUse spin coater to coat drug-loaded nanospheres on the surface of the slide uniformly and then put them in a tube containing phosphate buffered saline.The tubes were then placed in a shaking water bath at a thermostatic temperature to study the slow-release of the coating.Use the test to find the best conditions of rapamycin and paclitaxel's chromatographic conditions.Through the test we can analysis the effect of banknanoparticles coating and different content of blank nanoparticles coating and different cotent of rapamycin and paclitaxel to the drug slow-release.It can conclude that thedrug-loaded polycaprolatone nanoparticles that synthesis by desolvation method is water dispersible and have no migration of its surface.It can be used as drug coating and drug loadings can be controlled.Polycaprolatone without drug nanoparticles can slow the release of the drug.The increase content of drug can't faster the drug release.The addition of the enzyme can effectively accelerate the speed of the slow release of the drug especially the esterase.