Helena Gonzalez

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.

Sunscreen use: controversies, challenges and regulatory aspects.

Mismatches between skin pigmentation and modern lifestyle continue to challenge our naked skin. One of our responses to these challenges is the development and use of sunscreens. The management of sunscreens has to balance their protective effect against erythema, photocarcinogenesis and photoageing owing to the potential toxicity of the ultraviolet (UV) filters for humans and the environment. The protection against UV radiation offered by sunscreens was recently standardized in the European Union (EU) based on international harmonization of measurement techniques. Four different categories of sun protection have been implemented along with recommendations on how to use sunscreen products in order to obtain the labelled protection. The UV filters in sunscreens have long been authorized for use by the EU authority on the basis of data from studies on acute toxicity, subchronic and chronic toxicity, reproductive toxicity, genotoxicity, photogenotoxicity, carcinogenicity, irritation, sensitization, phototoxicity and photosensitization as well as on environmental aspects. New challenges with respect to the safety of UV filters have arisen from the banning of animal experiments for the development of cosmetics. Future debates on sunscreens are likely to focus on nanoparticles and environmental issues, along with motivation campaigns to persuade consumers to protect their skin. However, more efficient sunscreen use will also continue to raise questions on the benefit in preventing vitamin D synthesis in the skin induced by sunlight.

Nerve blocks enable adequate pain relief during topical photodynamic therapy of field cancerization on the forehead and scalp.

Background  Topical photodynamic therapy (PDT) is an effective method when treating extensive areas of sun‐damaged skin with multiple actinic keratoses (AKs) (field cancerization) on areas such as the forehead and scalp, and offers excellent cosmetic outcome. The major side‐effect of PDT is the pain experienced during treatment.

Photostability of commercial sunscreens upon sun exposure and irradiation by ultraviolet lamps.

BackgroundSunscreens are being widely used to reduce exposure to harmful ultraviolet (UV) radiation. The fact that some sunscreens are photounstable has been known for many years. Since the UV-absorbing ingredients of sunscreens may be photounstable, especially in the long wavelength region, it is of great interest to determine their degradation during exposure to UV radiation. Our aim was to investigate the photostability of seven commercial sunscreen products after natural UV exposure (UVnat) and artificial UV exposure (UVart).MethodsSeven commercial sunscreens were studied with absorption spectroscopy. Sunscreen product, 0.5 mg/cm2, was placed between plates of silica. The area under the curve (AUC) in the spectrum was calculated for UVA (320–400 nm), UVA1 (340–400 nm), UVA2 (320–340 nm) and UVB (290–320 nm) before (AUCbefore) and after (AUCafter) UVart (980 kJ/m2 UVA and 12 kJ/m2 of UVB) and before and after UVnat. If theAUC Index (AUCI), defined as AUCI = AUCafter/AUCbefore, was > 0.80, the sunscreen was considered photostable.ResultsThree sunscreens were unstable after 90 min of UVnat; in the UVA range the AUCI was between 0.41 and 0.76. In the UVB range one of these sunscreens was unstable with an AUCI of 0.75 after 90 min. Three sunscreens were photostable after 120 min of UVnat; in the UVA range the AUCI was between 0.85 and 0.99 and in the UVB range between 0.92 and 1.0. One sunscreen showed in the UVA range an AUCI of 0.87 after UVnat but an AUCI of 0.72 after UVart. Five of the sunscreens were stable in the UVB region.ConclusionThe present study shows that several sunscreens are photounstable in the UVA range after UVnat and UVart. There is a need for a standardized method to measure photostability, and the photostability should be marked on the sunscreen product.

Predictors of pain associated with photodynamic therapy: a retrospective study of 658 treatments.

Pain is the most common side-effect of photodynamic therapy (PDT). Our main objective was to identify pain predictors in PDT. In total, we performed 658 treatments on 377 patients at our department during 2004. Larger sized treatment areas were the strongest pain predictor, and actinic keratoses were more painful to treat than basal cell carcinomas and Bowens disease. The most sensitive areas to treat were the face and scalp. Gender and age did not influence pain. Although treatment outcome was not our primary objective, 62% of 95 superficial basal cell carcinomas that were followed for 3 years showed complete clearance. Also, perforation of nodular basal cell carcinomas did not lead to better clinical results. In conclusion, the size of the treatment area, the diagnosis and the lesion location influence pain during PDT. Nevertheless, there is a large variance in visual analogue scale assessment within each group, thereby limiting the ability to predict pain.

Percutaneous absorption with emphasis on sunscreens

Sunscreens are widely used products. When recreationally used they are applied to large areas of the skin repeatedly. In moisturizers and foundation it is common to find sun protective ingredients, in these cases the product is usually applied to smaller areas but often done daily. Active ingredients in sunscreens can be absorbed by the skin. Percutaneous absorption is an important factor to take into consideration. There are several methods to measure the percutaneous absorption, both in vivo and/or in vitro. This paper will give an overview of the different methods.

Solid-Phase Extraction and Reverse-Phase HPLC: Application to Study the Urinary Excretion Pattern of Benzophenone-3 and its Metabolite 2,4-Dihydroxybenzophenone in Human Urine

Background: Benzophenone-3 (BZ-3) is a common ultraviolet (UV) absorbing compound in sunscreens. It is the most bioavailable species of all UV-absorbing compounds after topical application and can be found in plasma and urine. Objectives: The aim of this study was to develop a reverse-phase high performance liquid chromatography (HPLC) method for determining the amounts BZ-3 and its metabolite 2,4-dihydroxybenzophenone (DHB) in human urine. The method had to be suitable for handling a large number of samples. It also had to be rapid and simple, but still sensitive, accurate and reproducible. The assay was applied to study the urinary excretion pattern after repeated whole-body applications of a commercial sunscreen, containing 4% BZ-3, to 25 healthy volunteers. Methods: Each sample was analyzed with regard to both conjugated/non-conjugated BZ-3 and conjugated/non-conjugated DHB, since both BZ-3 and DHB are extensively conjugated in the body. Solid-phase extraction (SPE) with C8 columns was followed by reverse-phase HPLC. For separation a Genesis C18 column was used with an acethonitrile-water mobile phase and the UV-detector was set at 287 nm. Results: The assay was linear r2 > 0.99, with detection limits for BZ-3 and DHB of 0.01 μmol L−1 and 0.16 μmol L−1 respectively. Relative standard deviation (RSD) was less than 10% for BZ-3 and less than 13% for DHB. The excretion pattern varied among the human volunteers; we discerned different patterns among the individuals. Conclusions: The reverse-phase HPLC assay and extraction procedures developed are suitable for use when a large number of samples need to be analyzed and the method fulfilled our objectives. The differences in excretion pattern may be due to differences in enzyme activity but further studies, especially about genetic polymorphism, need to be performed to verify this finding.

Incidence of cutaneous melanoma in Western Sweden, 1970-2007.

The aim of this study was to describe the increasing incidence of cutaneous malignant melanoma (CMM) in Western Sweden during the period 1970–2007. A secondary aim was to show a geographical variation in incidence between coastal and inland areas, considering the effects of the local average duration of sunshine, and the sun exposure-related behavior in the populations. The Swedish Cancer Registry provided data on invasive melanomas during 1970–2007. Meteorological maps showed the annual average duration of sunshine during 1961–1990. A survey from 2007 with 2871 participants, carried out by the National Board of Health and Welfare, provided data on self-reported sun exposure. During the period studied, the age-standardized incidence for men in Western Sweden more than quadrupled to 31.1/100 000 inhabitants, whereas it tripled for women to 27.1/100 000. Coastal areas, including Gothenburg city, had a high average duration of sunshine (1701–1900 h of sun/year), whereas inland areas had lower average duration of sunshine (⩽1700 h). The incidence of CMM was higher in coastal areas and in Gothenburg city, compared with inland areas. This may be linked to ultraviolet radiation, a consequence of the higher average duration of sunshine. The sun exposure survey showed additional factors, which possibly led to the increased incidence, for example high sun exposure on holidays abroad. The alarming increase in the incidence of CMM in Western Sweden, during the period 1970–2007, shows the need for additional primary preventive measures, for example sun protection programs targeted at populations in this area.

Diagnostic agreement and interobserver concordance with teledermoscopy referrals

Malignant melanoma and non‐melanoma skin cancers are among the fastest increasing malignancies in many countries. With the help of new tools, such as teledermoscopy referrals between primary health care and dermatology clinics, the management of these patients could be made more efficient.

对于患有光化性角化病的器官移植受者来说,光动力疗法比咪喹莫特更加有效:一项随机个体对照试验

器官移植(例如肾脏)受者必须服用强效药物来防止器官排斥。而这些药物也会降低人体抵御癌症病发的能力。这对皮肤来说尤其重要,来自阳光紫外线的伤害会导致暴露部位发生癌前病变(日光性角化症)。这些病变相当广泛,并且比在正常的健康皮肤上更容易发展成侵袭性皮肤癌。这项斯堪的纳维亚的研究在一组35名器官移植患者中比较了日光性角化症的两种确定治疗的有效性和可接受性。光动力疗法(PDT)在就诊时即可使用。它需要在皮肤上涂抹感光的乳膏,该乳膏随后会被红光激活。这会在皮肤上引发严重的炎症,但只会破坏异常(而非正常)的组织。另一种治疗是采用咪喹莫特乳膏,患者需每周在家涂抹三次,连续涂抹四周。该乳膏会刺激人体自身的防御机制,来抵抗异常组织病变。每位患者均拥有两处受到相同影响的皮肤部位。这些患者将被随机分配接受PDT或咪喹莫特治疗。如有必要,PDT治疗患者需在三个月后重复治疗,咪喹莫特治疗患者需在两个月后重复治疗。研究人员在三个月和六个月时计算了反馈率。本研究表明,在这组高风险患者中,光动力疗法在减少日光性角化症数量方面比咪喹莫特更加有效。由于PDT比咪喹莫特更加疼痛,患者并没有因此而更加倾向于哪一种治疗。