药脂比对米非司酮固体脂质纳米粒性能的影响

目的:将堕胎药物米非司酮载入固体脂质纳米粒(SLNs)中,研究药脂比对该体系性能的影响.方法:选用相同用量的4种表面活性剂,对SLN体系的平均粒径、Zeta电和包封率进行了测定,同时采用差示扫描量热法检测药物在载体中存在的晶型形态.结果:当脂质质量不变,SLN系统的平均粒径随所载药物量增加而增加.在载药量为50 mg,脂质质量为1 g时,包封率最高.同时,Zeta电位与胶体系统中游离药物量相关.DSC分析发现所有载药SLN试样均未出现米非司酮约190 ℃熔点附近的吸热峰.结论:载体所载模型药会影响系统的平均粒径和Zeta电位,即使在250 mg/1 g(脂质)的高载药量下,原本结晶性药物也是以无定形或者分子状态分散在SLN载体系统中的,目前尚未见到在如此高载药量下载体物理性状的相关报道.模型药米非司酮可以影响纳米系统的性能,另一方面,所加入药物的性能也被纳米尺度载体系统改变了.

Influence of Ratios of Drug to Lipid on the Characteristics of Solid Lipid Nanoparticles Containing Mifepristone

AIM:The effective abortifacient drug,mifepristone,was incorporated in the solid lipid nanoparticles (SLNs). The aim of this paper was to study the influence of ratios of drug to lipid on the characteristics of SLNs.METHOD:The physicochemical properties of the fine dispersed systems,such as the size distribution,Zeta potential had been analyzed by laser diffractometry(LD).The measurements of entrapment efficiency(EE)and thermal analysis of DSC were performed as well.RESULT:It was showed if the weight of lipid remained unchanged,the mean particle size of SLNs increased with the increase of drug amount.Drug entrapment efficiency was the highest while about 50 mg drug was loaded on weight 1 g lipid.Simultaneously,the charge of Zeta potential agreed well with the amount of free drug in the colloidal system.DSC analysis results showed that the melting peak of mifepristone at approx.190 ℃ disappeared.CONCLUSION:It was evidence that the drug incorporation would affect the average particle size and Zeta potential of the colloidal systems and the physical state of crystalline drug mifepristone in SLNs was present in the amorphous form or molecularly dispersed at even so high adding amount of 250 mg/g(lipid),which there was no report about the physical state of the drug and SLN with so high drug-loading.It was suggested that the model drug mifepristone could influence the property of nanodispersion system and the crystalline character of the drug was altered by the nanometer carrier system vice versa.