Characterization and formulation optimization of solid lipid nanoparticles in vitamin K1 delivery

Background: Solid lipid nanoparticle (SLN) systems have been applied to various drugs and delivery routes. Vitamin K1 is an important cofactor for maintaining hemostasis and preventing hemorrhage. Method: Vitamin K1-loaded SLNs are systematically being developed by optimizing triglycerides and lipophilic and hydrophilic surfactants based on the size and stability of the resulting SLNs. Concentrations of the surfactants, Myverol and Pluronic, were optimized by a central composite design and response surface methodology. Vitamin K1 (phylloquinone) was used as a lipophilic drug in the SLN system to evaluate the potential for oral delivery. Results: Vitamin K1-loaded SLNs had a mean size of 125 nm and a zeta potential of -23 mV as measured by photon correlation spectroscopy. The prepared SLNs were examined by differential scanning calorimetry and transmission electron microscopy and found to have an imperfect crystalline lattice and a spherical morphology. Effects of ultrasonication duration and drug load on the particle size and entrapment efficiency of the SLNs were also evaluated. Conclusion: More than 85 of the vitamin K1 was entrapped in SLNs when the payload was <5. The vitamin K1 in SLNs was stable for a 54-h duration in simulated gastric and intestinal fluids. The particle size and vitamin K1 entrapped in the SLN were stable after 4 months of storage at 25°C. The results demonstrated that SLNs prepared herein can potentially be exploited as carriers for the oral delivery of vitamin K1.