Development of a Novel Method for Fabrication of Solid Lipid Nanoparticles: using High Shear Homogenization and Ultrasonication

Solid Lipid nanoparticles (SLNs) were introduced at the beginning of 1990s as an alternative to solid nanoparticles, emulsions and liposomes in cosmetic and pharmaceutical preparations. The objective of the present investigation was to develop SLNs of capsaicin by a novel method using modified high shear homogenization and ultrasonication technique. In this method lipid matrix was melted and capsaicin was added to obtain a clear melting solution and this pre-emulsion was ultrasonicated to form nanoemulsion, which was then cooled to obtain the solid lipid nanosuspension. The prepared SLNs were characterized and evaluated for sustained release potential. The SLNs prepared were spherical in shape with the mean particle size of 100 nm with a small polydispersity index, 0.374. DSC studies showed less ordered arrangement of crystals, which was favorable for increasing the drug loading capacity. The entrapment efficiency, drug loading and zeta potential were 90.89%, 5.12% and -48.36 mV respectively. The cumulative amount of drug released in 1 hr from the capsaicin loaded SLNs was 6.5  0.3% compared with 95.8  4.1% from drug solution. Capsaicin release was steady and prolonged to 14 hr with SLNs encapsulation (94.33.8%). This study confirmed that the method developed is simple and effective to formulate SLNs of poorly soluble drugs without organic solvents.