METHODS: Palm kernel oil esters (PKOEs)-based nanoemulsions were loaded with P. urinaria extract using a spontaneous method and characterized with respect to particle size, zeta potential, and rheological properties. The release profile of the extract was evaluated using in vitro Franz diffusion cells from an artificial membrane and the antioxidant activity of the extract released was evaluated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method.
RESULTS: Formulation F12 consisted of wt/wt, 0.05% P. urinaria extract, 1% cetyl alcohol, 0.5% glyceryl monostearate, 12% PKOEs, and 27% Tween 80/Span 80 (9/1) with a hydrophilic lipophilic balance of 13.9, and a 59.5% phosphate buffer system at pH 7.4. Formulation F36 was comprised of 0.05% P. urinaria extract, 1% cetyl alcohol, 1% glyceryl monostearate, 14% PKOEs, 28% Tween 80/Span 80 (9/1) with a hydrophilic lipophilic balance of 13.9, and 56% phosphate buffer system at pH 7.4 with shear thinning and thixotropy. The droplet size of F12 and F36 was 30.74 nm and 35.71 nm, respectively, and their nanosizes were confirmed by transmission electron microscopy images. Thereafter, 51.30% and 51.02% of the loaded extract was released from F12 and F36 through an artificial cellulose membrane, scavenging 29.89% and 30.05% of DPPH radical activity, respectively.
CONCLUSION: The P. urinaria extract was successfully incorporated into a PKOEs-based nanoemulsion delivery system. In vitro release of the extract from the formulations showed DPPH radical scavenging activity. These formulations can neutralize reactive oxygen species and counteract oxidative injury induced by ultraviolet radiation and thereby ameliorate skin aging.
METHODS: 5-fluorouracil-loaded ethosomes were prepared and subjected to size, zeta potential, morphology, drug content, drug release and skin permeation tests. The molecular characteristics of untreated, microwave and/or ethosome-treated skins were examined by Fourier transform infrared and raman spectroscopy, thermal and electron microscopy techniques.
RESULTS: The skin drug retention was promoted using larger ethosomes with negative zeta potentials that repelled anionic lipids of skin and hindered vesicle permeation into deep layers. These ethosomes had low ethanol content. They were less able to fluidize the lipid and defluidize the protein domains at epidermis to enlarge aqueous pores for drug permeation. Pre-treatment of skin by 2450 MHz microwave for 2.5 min further increased skin drug penetration and retention of low ethanol ethosomes and provided lower drug permeation than cases treated for 1.15 min and 5 min. A 2.5 min treatment might be accompanied by specific dermal protein fluidization via C=O moiety which translated to macromolecular swelling, narrowing of intercellular spaces at lower skin layers, increased drug retention and reduced drug permeation.
CONCLUSION: Ethosomes and microwave synergized to promote skin drug retention.
METHODS: This work reports the application of an X-ray microbeam via synchrotron SAXS/WAXS analysis to monitor drug crystallization in the skin, especially in the deeper skin layers. Confocal Raman spectroscopy (CRS) was employed to examine drug distribution in the skin to complement the detection of drug crystallization using SAXS/WAXS analysis.
RESULTS: Following application of saturated drug solutions (ibuprofen, diclofenac acid, and salts), CRS depth profiles confirmed that the drugs generally were delivered to a depth of ~15 - 20 µm in the skin. This was compared with the WAXS profiles that measured drug crystal diffraction at a depth of up to ~25 µm of the skin.
CONCLUSION: This study demonstrates the potential of synchrotron SAXS/WAXS analysis for profiling of drug crystallization in situ in the deeper skin layers without pre-treatment for the skin samples. [Figure: see text].