Tretinoin cyclodextrin complex (RA/CyD) causes less irritation with an equal antiwrinkle effect compared with conventional tretinoin: clinical and histologic studies of photoaged skin

D-α-Tocopherol-Based Micelles for Successful Encapsulation of Retinoic Acid

All-trans-retinoic acid (ATRA) represents the first-choice treatment for several skin diseases, including epithelial skin cancer and acne. However, ATRA's cutaneous side effects, like redness and peeling, and its high instability limit its efficacy. To address these drawbacks and to improve ATRA solubilization, we prepared ATRA-loaded micelles (ATRA-TPGSs), by its encapsulation in D-α-tocopheryl-polyethylene-glycol-succinate (TPGS). First, to explore the feasibility of the project, a solubility study based on the equilibrium method was performed; then, six ATRA-TPGS formulations were prepared by the solvent-casting method using different TPGS amounts. ATRA-TPGSs showed small sizes (11-20 nm), low polydispersity, slightly negative zeta potential, and proved good encapsulation efficiency, confirmed by a chemometric-assisted Fourier transform infrared spectroscopy (FTIR) investigation. ATRA-TPGS stability was also investigated to choose the most stable formulation. Using Carbopol^® 980 as gelling agent, ATRA-TPGS-loaded gels were obtained and analyzed for their rheological profiles. Ex vivo release studies from ATRA-TPGSs were performed by Franz cells, demonstrating a permeation after 24 h of 22 ± 4 µ cm^-2. ATRA-TPGSs showed enhanced cytotoxic effects on melanoma cells, suggesting that these formulations may represent a valid alternative to improve patient compliance and to achieve more efficacious therapeutic outcomes.

Skin aging modulates percutaneous drug absorption: the impact of ultraviolet irradiation and ovariectomy

Ultraviolet (UV) exposure and menopause are known as the inducers of damage to the skin structure. The combination of these two factors accelerates the skin aging process. In this study, we aimed to evaluate the influence of UV and ovariectomy (OVX) on the permeation of drugs through the skin. The role of tight junctions (TJs) and adherens junctions (AJs) in the cutaneous absorption of extremely lipophilic permeants and macromolecules was explored. The OVX nude mouse underwent bilateral ovary removal. Both UVA and UVB were employed to irradiate the skin. The physiological and biochemical changes of the skin structure were examined with focus on transepidermal water loss (TEWL), skin color, immunohistochemistry, and mRNA levels of proteins. UVB and OVX increased TEWL, resulting in stratum corneum (SC) integrity disruption and dehydration. A hyperproliferative epidermis was produced by UVB. UVA caused a pale skin color tone due to keratinocyte apoptosis in the epidermis. E-cadherin and β-catenin showed a significant loss by both UVA and UVB. OVX downregulated the expression of filaggrin and involucrin. A further reduction was observed when UV and OVX were combined. The in vitro cutaneous absorption demonstrated that UV increased the skin permeation of tretinoin by about twofold. However, skin accumulation and flux of estradiol were not modified by photoaging. OVX basically revealed a negligible effect on altering the permeation of small permeants. OVX increased tretinoin uptake by the appendages from 1.36 to 3.52 μg/cm(2). A synergistic effect on tretinoin follicular uptake enhancement was observed for combined UV and OVX. However, the intervention of OVX to photoaged skin resulted in less macromolecule (dextran, molecular weight = 4 kDa) accumulation in the skin reservoir because of retarded partitioning into dry skin. The in vivo percutaneous absorption of lipophilic dye examined by confocal microscopy had indicated that the SC was still important to controlling topical delivery, although the role of epidermal junctions could not be simply ignored.

Comparative evaluation of wrinkle treatments

BACKGROUND

Skin wrinkles are one of the most cosmetically concerning signs of aging for women, and improvements in the visual effect of wrinkles become a matter of concern that has an impact on the quality of life. Although various wrinkle treatments are being tried in the area of aesthetics and noninvasive cosmetic surgery, no guideline on how to treat wrinkles exists to date. This study evaluated the clinical effects of four wrinkle treatment methods [fractional erbium yttrium-aluminum-garnet (YAG) laser treatment, intense pulsed light (IPL) therapy, CD-atRA external application, and nutritional therapy with intake of amino acid supplements]. These four methods were selected as promising candidates in a pilot case study to improve wrinkles by following the consensus guideline (Task Force Committee for Evaluation of Anti-Aging Function, J Jpn Cosmet Sci Soc 31:411-431, 2007) for the evaluation of anti-wrinkle effects issued by the Japan Cosmetic Industry Association.

METHODS

The wrinkle area fraction and skin viscoelasticity were measured by objective evaluation. Furthermore, a satisfaction survey of the subjects was conducted on the basis of subjective evaluations using the visual analog scale (VAS) method and in accordance with the guideline for the evaluation of antiwrinkle effects.

RESULTS

Fractional erbium YAG laser treatment showed statistically significant improvement in both of the objective evaluations (wrinkle area and skin elasticity). The IPL method showed statistically significant improvement in both of the objective evaluations (wrinkle area and skin elasticity), and it especially demonstrated a more significant difference in skin elasticity. The CD-tretinoin external application method showed statistically significant improvement in both of the objective evaluations (wrinkle area and skin elasticity), and it especially demonstrated a more significant difference in wrinkle area. Nutritional therapy showed statistically significant improvement in wrinkle area, whereas IPL, CD-tretinoin external application, and nutritional therapy demonstrated statistically significant improvement in the degree of wrinkle. As for the subjective assessment of VAS, all four treatments demonstrated equivalent satisfaction.

CONCLUSION

All four minimally invasive procedures (fractional erbium YAG treatment, IPL therapy, CD-atRA external application, and intake of amino acid supplements) showed significant improvement of wrinkles. Comparative evaluation of wrinkles using the same criteria is important. The findings clearly showed that an evidence-based approach to wrinkle treatments supported by validation of their effectiveness is required.

LEVEL OF EVIDENCE IV

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