Formulation, Characterization and in vitro Evaluation of Methotrexate Solid Lipid Nanoparticles

Solid lipid nanoparticles (SLNs) of methotrexate were produced by microemulsion method in an acidic aqueous system. The SLNs were composed of low melting fatty acid (glyceryl monostearate), surfactants (Egg lecithin and tween 80) and water. All the formulations were subjected to particle size analysis, zeta potential, drug entrapment efficiency and in vitro release studies. The SLNs formed were in nano-size range with maximum entrapment efficiency. Formulation with 253 nm in particle size and 85.12% of drug entrapment was subjected to scanning electron microscopy (SEM) for surface mophology, differential scanning calorimetry (DSC) for thermal analysis and short term stability studies. SEM confirms that the SLNs are circular in shape. The drug release behavior from SLN suspension exhibited biphasic pattern with an initial burst and prolonged release over 24 h.