Study On The Preparation Of Paclitaxel-loaded Microcapsules By Supercritical Emulsion Extraction

Paclitaxel is a natural substance that can effectively fight cancer,but its traditional preparation method has a series of problems such as poor water solubility and stability,and large toxic and side effects.If the polymer is used to coat the paclitaxel to form the microcapsules,the deficiency can be avoided.In this study,the supercritical emulsion extraction method was used to prepare the PLGA-loaded paclitaxel microcapsules.The SFEE method is an improvement of the supercritical fluid anti-solvent method.The research is mainly based on experimental research,which provides an experimental basis for determining an efficient supercritical method for preparing paclitaxel nanoparticles.In this paper,firstly,combined SFEE method and oil-in-water emulsion preparation technology,PLGA microcapsules containing paclitaxel were prepared.Combining the empirical formula of diffusion coefficient and the critical mixing point of the binary system?EA/CO₂?,the miscibility of SC-CO₂ and organic solvents under different operating parameters can be determined,as well as the change of the diffusion rate of SC-CO₂ in the continuous phase.Research results It was shown that the minimum residual solvent content was 0.005mg/L for 40 min extraction under the conditions of 60?,9 MPa,and 0.4 L/min.On this basis,the effects of different operating conditions on the particle size and morphology of the microcapsules were explored.The results of the study showed that the PLGA mass concentration was within the range of 1%-10%,and the particle size of the microcapsules increased from 1.016?m to 2.610?m.The particle size of the microcapsules can be effectively controlled by changing the parameters of the emulsion.The formed microcapsules have uniform particle size distribution,good dispersion effect,high sphericity,clear interfaces between microcapsules and no adhesion.The FT-IR and XRD characterization methods were used to study the changes in the chemical structure and crystallization behavior of the microcapsules,core and wall materials before and after SFEE treatment.Studies have shown that there are no new chemical bonds in the drug-loaded microcapsules after SFEE treatment,and only hydrogen bond interactions or intermolecular forces exist between them,so it can indicate that paclitaxel is effectively coated in PLGA.The embedding rate is an important indicator to measure the embedding effect of microcapsules.The single factor experiment is designed to study the influence of different operating parameters on the embedding rate,and the main factors affecting the embedding rate of microcapsules are determined.On the basis of response surface analysis,the influence degree of each influencing factor on the embedding rate is determined,and the optimal parameters of the microcapsule and the maximum embedding rate under this parameter are obtained.The results of the study show that the response value of the embedding rate is affected by each influencing factor from large to small:wall material mass concentration>Tween mass concentration>water-oil ratio.PLGA mass concentration and Tween mass concentration,PLGA mass concentration and water-oil ratio have a strong interaction on the microcapsule embedding rate.The Tween mass concentration is 1%,the PLGA mass concentration is 10%,and the water-oil ratio is 1:2.Under these conditions,the maximum embedding rate of microcapsules is 96.82%.The microcapsule embedding rate can be effectively controlled by controlling the emulsion preparation parameters.To study the release characteristics of microcapsules in PBS/ethanol buffer,investigate the influence of emulsion preparation parameters on the release characteristics of microcapsules,and use different release kinetic equations to fit the data.The research shows that the sustained release law of microcapsules conforms to the Weibull equation.The mass concentration of PLGA and Tween in the emulsion preparation parameters can significantly affect the sustained release characteristics of the microcapsules.The release rule is in accordance with the embedded paclitaxel to realize the treatment of human body.