Vitamin K1-loaded lipid-core nanocapsules: physicochemical characterization and in vitro skin permeation.

BACKGROUND: The incorporation of substances in nanocarriers can modulate and/or manage their delivery profiles (immediate or sustained) and permeation through skin. Consequently, drug nanencapsulation intended for topical treatment can reduce the systemic absorption of the substance. OBJECTIVE: To obtain and characterize vitamin K1-loaded lipid core nanocapsules as well as to determine whether the nanoencapsulation influences the skin permeation of this vitamin. METHODS: The skin permeation study was performed by means of Franz-type diffusion cells followed by the tape stripping and retention techniques. The vitamin K1-loaded lipid core nanocapsules were obtained by the preformed polymer precipitation method and the particles were characterized. RESULTS: The nanocapsules presented average diameter of 211 ± 2 nm, pH of 5.7 ± 0.3, zeta potential of -14.9 ± 0.6 mV and drug content of 10.2 mg/mL (102.1%). The physical stability of the nanocapsule suspension was verified using multiple light backscattering analysis. The amount of vitamin K1 in the dermis after 8 h of drug permeation was higher when the nanocapsules were applied compared to the control. Moreover, retention in the outermost skin layer and a decrease in the skin permeation to the receptor compartment due to the nanoencapsulation were observed. CONCLUSION: Thus, nanoencapsulation can lead to the selective permeation of vitamin K1 through the skin.

Combined effect of polymeric nanocapsules and chitosan hydrogel on the increase of capsaicinoids adhesion to the skin surface.

This work explored the effect of the encapsulation in polymeric nanocapsules, as well as of the incorporation of such nanoparticles in a chitosan hydrogel, on the skin adhesion and skin penetration/permeation of capsaicinoids (capsaicin and dihydrocapsaicin), which are used as topical analgesic to treat chronic pain. The skin experiments were performed using a modified (drug adhesion and drug diffusion) and a normal Franz diffusion cell (drug diffusion) with porcine skin as membrane. The AUC0-h of the washability profile (% washed away vs. time) determined for the formulation combining both factors studied (chitosan hydrogel containing drug-loaded nanocapsules) was 198.88 +/- 10.05/153.53 +/- 5.99, for capsaicin and dihydrocapsaicin respectively, significantly lower than the values observed for the chitosan hydrogel containing free drug (291.57 +/- 3.83/278.18 +/- 5.28) and for the hydroxyethyl cellulose containing drug-loaded nanocapsules (245.47 +/- 13.18/197.69 +/- 15.78). By adequate fitting to the monoexponential first order equation, the washing rate values indicated that the nanocapsules were more efficient in increasing the drugs skin adhesion than the chitosan gel. Regarding the skin penetration/permeation study, after washing the skin, the formulation which presented the lowest washing rate (chitosan gel containing nanocapsules) was the one which led to a higher amount of capsaicinoids in the skin layers (epidermis and dermis). Without washing the skin, the nanoencapsules caused retention of the drugs in the outer skin layer (epidermis). In conclusion, the skin adhesion of the nanocapsules and their capability of controlling the drug diffusion were shown. Combining chitosan gel to nanocapsules led to a formulation of great skin bioadhesion.