Influence of lipids on the properties of solid lipid nanoparticles from microemulsion technique.

Solid lipid nanoparticles (SLN) are colloidal lipid carriers widely employed as efficient drug delivery systems. In this report, SLN were produced by microemulsion technique, and the influence of lipid composition on the physical properties of SLN was evaluated. Lipids with different molecular structures in carbon number of the fatty acid residue and their polarity were selected (i.e., glyceryl trimyristate, glyceryl tripalmitate, glyceryl tristearate, stearic acid, and glyceryl monostearate). A warm oil-in-water microemulsion containing 7% lipid, 30% water, and 63% surfactant mixture (polysorbate 80:1-butanol 4:1) was prepared by simple mixing at 60°C, following its dilution in cold water at various ratios at constant stirring. The obtained SLN were analyzed for appearance, particle size, zeta potential, and sedimentation rate. The chemical structure of the selected lipids affected both the microemulsion formation and the physical characteristics of SLN. From the obtained results, a dilution ratio of 1:50 was selected for the production of SLN composed of glyceryl trimyristate as solid lipid matrix. The obtained particles were of 154.9 ± 0.7 nm mean particle size, with a polydispersity index (PI) of 0.274 and zeta potential of −7.46 ± 0.68 mV. Practical applications: The methodology presented here describes the application of microemulsion technique on processing different lipid compositions, to develop and produce an optimal SLN formulation using pseudoternary phase diagrams. Microemulsion technique is well-known for preparation SLN by adding a warm oil-in-water microemulsion, which can be spontaneously formed, when diluted in a large volume of cold water. The data presented in this paper show that the molecular structures of lipids influenced both the microemulsion formation and the physical characteristics of the resulting SLN. The optimal SLN formulation could be developed. [ABSTRACT FROM AUTHOR]