Optimization of β-carotene loaded solid lipid nanoparticles preparation using a high shear homogenization technique

Using statistical experimental design methodologies, the solid lipid nanoparticle design space was found to be more robust than previously shown in literature. Formulation and high shear homogenization process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated. Experimentation indicated stearic acid as the optimal lipid, sodium taurocholate as the optimal cosurfactant, an optimum lecithin to sodium taurocholate ratio of 3:1, and an inverse relationship between mixing time and speed and nanoparticle size and polydispersity. Having defined the base solid lipid nanoparticle system, beta-carotene was incorporated into stearic acid nanoparticles to investigate the effects of introducing a drug into the base solid lipid nanoparticle system. The presence of beta-carotene produced a significant effect on the optimal formulation and process conditions, but the design space was found to be robust enough to accommodate the drug. beta-Carotene entrapment efficiency averaged 40%. beta-Carotene was retained in the nanoparticles for 1 month. As demonstrated herein, solid lipid nanoparticle technology can be sufficiently robust from a design standpoint to become commercially viable.