Preparation Of Risperidone Microspheres By SPG Membrane Emulsification

Mental illness brings serious harm to human health.Characterized by good efficacy and little side effects,the second-generation antipsychotic medication risperidone can treat the positive and negative symptoms of mental illness.The general preparations currently sold in the market can merely meet patients’ short-term treatment,but for those psychiatric patients,it is difficult to take medicine regularly in long period.Although there are some long-acting sustained-release drug products in the market at present,they also show some drawbacks in production process and drug attribultes,such as a long period of stagnation,the relatively low uniformity of microsphere particle sizes,which needs to be sieved,as well as the difficult removal process of organic solvents.To address the inadequate existing long-acting risperidone microsphere preparations,in this study we tried to develop the process of preparing risperidone microspheres via membrane emulsification.In the study the analysis method in vitro of risperidone was first developed and validated t;then theoretical analysis on the phase factor,membrane emulsification process factor and lyophilization factor in the process of preparing risperidone microspheres via membrane emulsification was conducted,and experimental research on the key process parameters of each factor was made;specialized instruments was utilized,such as a lyophilization microscope and low-temperature DSC,which is to detect the lyophilization parameters of microsphere suspension,and our focused research on the lyophilization process in combination of experimental design software was carried out;and finally the process stability of three batches of the screened process parameters was verified,and the quality of the prepared microsphere was compared,with that of the microsphere prepared via the conventional in-liquid solvent evaporation method.During the course of studying the process parameters,the laws of the influences of dosage,membrane pore size,curing temperature and analytical drying temperature on the microsphere quality were analyzed,and the process method of preparing risperidone PLGA microspheres via SPG membrane emulsification was eventually developed.By adopting this process method,the microspheres with round appearance,high particle size uniformity and low organic solvent residual can be prepared,and the stagnation period of the microspheres’ in vitro release is short.Comparing the quality features of the microspheres prepared via the two methods,it is found that the particle size and uniformity of the microsphere prepared via membrane emulsification are better than those of microsphere prepared via the in-liquid solvent evaporation method and its organic solvent residual is lower.Furthermore,by the strength of stable process parameters and easy operation,this process method can be applied to industrial production more quickly;and on the basis of this process,it is expected to develop the large-scale production process that can obtain the risperidone long-acting sustained-release preparations with a better quality.