ABSTRACT
AIM:Surfactants and their blend play important roles in the preparation of solid lipid nanoparticles (SLNs).In this study,four types of surfactant were employed to investigate the influence of the surfactants on properties of SLNs in the absence of model drugs thereby avoiding the interaction between the surfactant and the drug.METHODS:The physicochemical properties of the colloidal systems,such as mean particle size,distribution range and Zeta potential,were investigated by laser diffractometry and the DSC analysis was performed as well.RESULTS:It was found that ionic surfactants,such as sodium deoxycholate, increased the Zeta potential of nanoparticles leading to improve the physical stability of the system.But it showed obviously relative low emulsification efficiency in the preparation.Non-ionic emulsifier,especially Pluronic F-68, offered additional steric stabilization effect avoiding aggregation of the fine particles in the colloidal system.CONCLUSION:The formulation in the study for the first time combined four types of additives including ionic surfactant (sodium deoxycholate),non-ionic emulsifier (Pluronic F-68 and Tween-80),and lecithin to obtain favorably stable nanosuspension,which could stabilize for more than six months without creaming.
ABSTRACT
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.