Study On Preparation Of Drug-loaded Microcapsules And Magnetic Composite Microcapsules By Supercritical Fluid Extraction Of Emulsions

Some drugs are limited in daily use due to poor water solubility,susceptibility to oxidation,and low bioavailability.Polymer-loaded microcapsules can effectively solve the above problems.In this paper,polymer-loaded microcapsules and magnetic composite microcapsules were successfully prepared by Supercritical Fluid Extraction of Emulsion?SFEE?.The SFEE method,as a new method for preparing microcapsules using supercritical fluids,can be regarded as an optimization of supercritical anti-solvent technology?SAS?,which can effectively improve the organic solvent in traditional microcapsule preparation methods.Removal and other supercritical fluids in the microcapsule preparation method are difficult to control particle size.The specific research contents are as follows:In terms of organic solvent removal efficiency,the miscibility of organic solvents with supercritical carbon dioxide?SC-CO₂?is a key factor in determining the extraction efficiency in the SFEE process.In this paper,the critical point of the EA/CO₂ binary system is calculated by Matlab.Combined with the experimental results of different extraction temperature,pressure and CO₂ flow rate,the extraction is carried out under the conditions of313 K,9 MPa and 0.4 L/min for 40 min.The lower amount is 59 mg/L.In terms of particle size control,the preparation of emulsion parameters is the most effective method to control the particle size of microcapsules.PCL mass concentration is 1%,2.5%,5%,7.5%,10%under microcapsules.The average particle diameters were 0.9,1.8,2.3,3.2,and 3.7?m,respectively.Electron microscopy?SEM?,Fourier transform infrared spectroscopy?FITR?,etc.showed that the prepared microcapsules had high sphericity,no aggregation and quercetin was coated with polycaprolactone?PCL?.The main factors and levels affecting the microencapsulation rate were determined by single factor method.The response surface method was used to optimize the experimental conditions and the relationship between the main factors was analyzed.The quadratic diversity with the embedding rate was established.The mathematical model was regressed and the microencapsulation rate under different conditions was successfully predicted.By fitting the release data of microcapsules,it was found that the microcapsule slow release law of different PCL mass concentrations accorded with the Weibull equation.In order to realize the targeting function of the drug-loaded microcapsules,the nano-sized lipophilic iron powder prepared by the coprecipitation method is added in the preparation process.Particle size analysis and other means showed that the prepared lipophilic nano-iron powder has uniform particle size distribution and good dispersibility in the oil phase.SEM,vibrating magnetometer?VSM?and other characterization methods show that the prepared magnetic composite microcapsules have uniform particle size,smooth surface and good magnetic response capability,which meets the requirements of targeted drug carriers.