Assessment of a Novel Vitamin D-3 Formulation with Nanostructured Lipid Carriers for Transdermal Delivery

Objective: Develop and assess a transdermal emulsion loaded with nanostructured lipid carriers for vitamin D-3 supplementation. Methods: Vitamin D-3 loaded nanostructured lipid carriers, produced via high shear homogenization and ultrasonication, were assessed for their particle size, distribution, morphology. zeta potential. entrapment efficiency, and cytotoxicity. They were incorporated into a transdermal vehicle, and the stability and ex vivo permeation were evaluated. Results: Spherical nanoparticles were developed with a particle size of 192.5 nm, a polydispersity index of 0.13, a zeta potential of -29.0 mV, and an entrapment efficiency of 99.75%. They were stable (particle size and distribution) for 15 days when stored in a refrigerator, and for 30 days at room temperature and 32 degrees C. The nanoparticles decreased the drug cytotoxicity against fibroblasts, as shown by IC50 (nanoparticle: 32.48 mu g mL(-1); vitamin D-3: 16.73 mu g mL(-1)). The emulsion loaded with nanoparticles minimized the degradation of vitamin D-3 when compared with the nanoparticle dispersion. Additionally, the emulsion provided the skin permeation of vitamin D-3 following the recommended daily allowance. Conclusion: To the best of our knowledge, this is the first study to use nanostructured lipid carriers for transdermal delivery of vitamin D. The developed formulation is a promising strategy to overcome the vitamin D-3 variable oral bioavailability. It also represents a comfortable route of administration; thus it could be beneficial for patients and clinicians. However, further studies are needed to allow the permeation of larger amounts of vitamin D-3, and the combination of these nanoparticles with microneedles would be interesting.