Update on photoprotection

ABSTRACT:  Photoprotection is an effective method for preventing damaging effects from ultraviolet radiation (UVR). Photoprotection is accomplished through the use of sunscreens, protective clothing, and safe sun practices. Sunscreens are composed of various UV filters, including inorganic/physical blockers and organic/chemical sunscreen agents. New technologies are emerging in sunscreen development and may soon be available to U.S. consumers. General guidelines for sunscreen use should be reinforced to improve patient compliance and sunscreen efficacy. Habitual use of sunscreen is recommended with UV exposure, and concerns for vitamin D deficiency with sunscreen use should not supersede proper photoprotective behavior.     

Percutaneous absorption of the sunscreen benzophenone-3 after repeated whole-body applications, with and without ultraviolet irradiation

BACKGROUND: Benzophenone-3 (BZ-3; 2-hydroxy-4-methoxybenzophenone, oxybenzone) is commonly used to absorb ultraviolet (UV) radiation. BZ-3 penetrates the skin and can be found in the urine. The amount varies between 0.4% and 2%. This seems to be the main metabolic pathway in rats. OBJECTIVES: To investigate the total amount of BZ-3 excreted in the urine after repeated topical whole-body applications of a sunscreen and to see if UV radiation has any effect on the amount excreted. METHODS: Twenty-five volunteers applied a commercially available sunscreen containing 4% BZ-3 morning and night for 5 days. Their urine was measured during those 5 days and during a further 5 days after the last application. They were divided into groups A (unirradiated) and B. Group B received UV radiation according to skin type: UVA between 400 and 707 J cm(-2), and UVB between 0.46 and 2.0 J cm(-2). BZ-3 in urine was analysed with a high-performance liquid chromatography method. RESULTS: The volunteers excreted 1.2-8.7% (mean 3.7%) of the total amount of BZ-3 applied. There was no significant difference between the two groups (P < 0.99, t-test). CONCLUSIONS: We show that a large amount of BZ-3 is absorbed. BZ-3 is accumulated in the body as the volunteers excreted BZ-3 5 days after the last application.     

Clinical fetal monitoring

Abstract

Ultraviolet (UV) radiation is a notorious environmental carcinogen. Acute and chronic UV radiation exposure increase the risk for skin cancer. Protecting oneself from both UVA and UVB radiation with broad-based sunscreen can prevent certain skin cancers, their precursors, and photoaging. Although sun protection factor only measures UVB protection, it is essential to consider protection from UVA radiation when deciding on a particular sunscreen product. Awareness of particular controversies associated with sunscreen, such as vitamin D deficiency and sunscreen toxicity, is necessary to adequately counsel patients with sunscreen concerns. Additionally, all physicians should be familiar with sunscreen composition, proper use, and benefits while encouraging patient compliance.