| Abstrakt: |
Background: Long wavelength ultraviolet‐A1 in combination with visible light induces hyperpigmentation, particularly in dark‐skin phototypes. This study evaluated the efficacy of four sunscreen formulations in protecting against VL + UVA1 (370–700 nm). Methods: The test products (A–D) were applied to the back of 12 volunteers, then irradiated with 320 J/cm2 VL + UVA1 (3.5% UVA1 [370–400 nm]). Immediately after irradiation, and at Days 1, 7, and 14, erythema and pigmentation were assessed by investigator global assessment (IGA), colorimetry (Δa* and ΔITA) and diffuse reflectance spectroscopy (DRS)‐measured relative dyschromia (area under the curve AUC). Control areas were irradiated without sunscreen. Results: Product D, containing titanium dioxide 11%, iron oxides 1%, and antioxidants, provided the highest and most consistent protection. Compared with unprotected irradiated control, it had statistically significantly less erythema on IGA, DRS (Δoxyhemoglobin), and colorimetry (Δa*) at Day 0; less pigmentation on IGA at all time points, on DRS (relative dyschromia) at Days 7 and 14, and on colorimetry (ΔITA) at Day 0. Product B, containing zinc oxide 12% plus organic UV filters, iron oxides 4%, and antioxidants, also showed some efficacy. Conclusion: Of the sunscreens tested, the tinted products provided better protection against VL + UVA1 than the non‐tinted products. Since the product with 1% iron oxides was superior to the product with 4% iron oxides, further studies are needed to evaluate whether iron oxide content correlates with better protection. [ABSTRACT FROM AUTHOR] |
Plný text