To examine the influence of the structural parameters and working parameters of a double-drum regeneration mixing station on its mixing uniformity,the influence of the discrete element method and response surface meth...To examine the influence of the structural parameters and working parameters of a double-drum regeneration mixing station on its mixing uniformity,the influence of the discrete element method and response surface method on the uniformity of the aggregate mixing when the interaction between two different factors was analyzed.A mathematical model of the influence of various factors and interactions on the coefficient of variation of the aggregates was established.The matching of each parameter was optimized with the goal of minimizing the coefficient of variation.The results show that when the aggregate particle size is different,the significance of each parameter affecting its mixing uniformity is also different.Moreover,increasing the speed and reducing the axial installation angle of the blade can reduce the coefficient of variation of the three aggregates.To obtain a good mixing uniformity,the mixing-arm phase angle when the drum inclination angle is large should be smaller than the phase angle when the drum inclination angle is small,and the mixing of large particles should not be arranged with a large mixing-arm phase angle.With a blade radial installation angle of 38°,a blade axial installation angle of 35°,a drum inclination angle of 6°,a drum rotation speed of 10 r/min,and a mixing-arm phase angle of 32°,the aggregate as a whole can exhibit the best mixing uniformity.展开更多
文摘作为一种新型酰胺类局部麻醉药,罗哌卡因(ROP)被广泛用于术后的疼痛管理中。ROP半衰期短(t_(1/2)=1.8 h),临床上为满足患者的镇痛需求,常需多次给药,导致患者顺应性差。采用复乳-溶剂挥发法结合快速膜乳化技术制备ROP-PLGA微球,最终在外水相PVA浓度1.5%(w/v)、油相与外水相(O/W_(2))体积比1:7.5、复乳液搅拌速率300 r/min、过膜压力10 k Pa条件下得到粒径为7.831μm,Span值为0.874的均一PLGA微球。基于响应面法设计实验考察了外水相pH、油相PLGA浓度、内水相与油相(W1/O)体积比等因素对微球包埋率及载药量的影响,模型优化的条件:外水相pH为11、油相PLGA浓度为15%(w/v)、内水相与油相(W1/O)体积比1:10。模型预测载药量为17.6μg/mg,包埋率53.89%,重复性验证实验测得载药量(18.0±0.5)μg/mg,包埋率(55.7±2.69)%,相对误差小于7%,证明模型可靠。体外释放结果显示,3天累计释放率约为50%,5天累计释放率约为70%,表明制备的ROP-PLGA微球具有平稳的缓释作用,微球制剂在局麻药缓释领域具有巨大的潜力。
基金The Natural Science Basic Research Plan in Shaanxi Province(No.2017JM5077)the Fundamental Research Funds for the Central Universities under Grant(No.300102259109).
文摘To examine the influence of the structural parameters and working parameters of a double-drum regeneration mixing station on its mixing uniformity,the influence of the discrete element method and response surface method on the uniformity of the aggregate mixing when the interaction between two different factors was analyzed.A mathematical model of the influence of various factors and interactions on the coefficient of variation of the aggregates was established.The matching of each parameter was optimized with the goal of minimizing the coefficient of variation.The results show that when the aggregate particle size is different,the significance of each parameter affecting its mixing uniformity is also different.Moreover,increasing the speed and reducing the axial installation angle of the blade can reduce the coefficient of variation of the three aggregates.To obtain a good mixing uniformity,the mixing-arm phase angle when the drum inclination angle is large should be smaller than the phase angle when the drum inclination angle is small,and the mixing of large particles should not be arranged with a large mixing-arm phase angle.With a blade radial installation angle of 38°,a blade axial installation angle of 35°,a drum inclination angle of 6°,a drum rotation speed of 10 r/min,and a mixing-arm phase angle of 32°,the aggregate as a whole can exhibit the best mixing uniformity.
