Nanoparticles are ultra fine colloidal structures, which carry drug particles that may not dissolve but remains suspended in medium. These are colloidal particles ranging size from 10-1000nm. The aim of the work is to improve the oral bioavailability of the poorly water soluble drugs by incorporating as solid lipid nanoparticle. Behenic acid and stearic acid was used as lipid solid matrix and the method of preparation is Microemulsification solidification. Methotrexate was selected as model drug. The drug was dissolved in the melted lipid to form microemulsion, which was then added to cold water under mechanical stirring. The resulting nanosuspension was then filtered by ultrafiltration. The prepared nanosuspension was then freeze dried. The nanoparticles are evaluated for particle size, drug entrapment efficiency and Invitro drug release. SLN were further characterized by SEM, X ray diffraction studies. Lyophilization of the nanosuspension with different cryoprotectant such as Trehalose and Fructose were performed. Trehalose containing formulation found to give best reconstitution behaviour. Drug dissolution studies of SLN was compared with that of commercial suspension and found to have SLN giving prolonged drug release. The result of the study indicates that poorly water soluble drugs can be formulated as nanoparticles to improve the bioavailability.
