Mexenone

Sensitivity to sunscreens

The patients sensitised to sunscreen agents who attended our Contact Dermatitis Clinic between February 1985 to March 1987 have been reviewed. 15 (5%) of 280 patients tested with sunscreens had positive reactions; 3 of them were allergic to more than one agent. The most frequent contact allergens were hydroxy methoxy methyl benzophenone (Mexenone) [6], followed by isopropyl dibenzoylmethane (Eusolex 8020/8021) [5], octyl dimethyl para-aminobenzoate (Escalol 507) [2], and one reaction each to butyl methoxy dibenzoylmethane (Parsol 1789), amyl dimethyl para-aminobenzoate (Escalol 506), and ethoxy ethyl-p-methoxy cinnamate (Givtan F). Positive photopatch tests were seen with isopropyl dibenzoylmethane, butyl methoxy dibenzoylmethane, para-aminobenzoate (PABA) and ethoxy ethyl-p-methoxy cinnamate, one reaction each.

Using Bibliometric Analysis and Machine Learning to Identify Compounds Binding to Sialidase-1

Rare diseases impact hundreds of millions of individuals worldwide. However, few therapies exist to treat the rare disease population because financial resources are limited, the number of patients affected is low, bioactivity data is often nonexistent, and very few animal models exist to support preclinical development efforts. Sialidosis is an ultrarare lysosomal storage disorder in which mutations in the NEU1 gene result in the deficiency of the lysosomal enzyme sialidase-1. This enzyme catalyzes the removal of sialic acid moieties from glycoproteins and glycolipids. Therefore, the defective or deficient protein leads to the buildup of sialylated glycoproteins as well as several characteristic symptoms of sialidosis including visual impairment, ataxia, hepatomegaly, dysostosis multiplex, and developmental delay. In this study, we used a bibliometric tool to generate links between lysosomal storage disease (LSD) targets and existing bioactivity data that could be curated in order to build machine learning models and screen compounds in silico. We focused on sialidase as an example, and we used the data curated from the literature to build a Bayesian model which was then used to score compound libraries and rank these molecules for in vitro testing. Two compounds were identified from in vitro testing using microscale thermophoresis, namely sulfameter (K _d 2.15 ± 1.02 μM) and mexenone (K _d 8.88 ± 4.02 μM), which validated our approach to identifying new molecules binding to this protein, which could represent possible drug candidates that can be evaluated further as potential chaperones for this ultrarare lysosomal disease for which there is currently no treatment. Combining bibliometric and machine learning approaches has the ability to assist in curating small molecule data and model building, respectively, for rare disease drug discovery. This approach also has the capability to identify new compounds that are potential drug candidates.

Photopatch testing in Asians: a 5-year experience in Singapore

Background: Photopatch testing is important for diagnosing photoallergic contact dermatitis. We aimed to evaluate the use of photopatch test at the National Skin Centre, Singapore.
Methods: All patients who had photopatch tests done between 2007 and 2011 at the National Skin Centre were included.
Results: Twenty-two patients were included. The mean age was 40.2. Female : male ratio was 3.4. The ethnic groups were Chinese (68%), Malay (4%), Indian (14%) and others (14%). Ten out of 22 patients (45.5%) had a positive photopatch test. There were 20 positive photopatch test reactions found in these 10 patients, and all 20 positive reactions were of current relevance. The frequencies of the positive photopatch test reactions were 2-hydroxy-4-methoxybenzophenone (oxybenzone) (n = 6), 2-hydroxymethoxymethylbenzophenone (mexenone) (n = 3), 2-ethylhexyl-4-dimethylaminobenzoate (n = 1), ketoprofen gel (n = 1) and the patient's own product (n = 9).
Conclusions: Our study suggests that sunscreen is the most common photoallergen to date as opposed to musk ambrette, which was the most common photoallergen in our earlier study in 1991-1993. This finding is similar to the recent European Multicentre Photopatch Test Study.

Contact allergy from Mexenone masquerading as an exacerbation of light sensitivity

A study of chemical light screening agents

In a group of 104 non-photosensitive subjects and seventy-eight suffering from a variety of photodermatoses, the most effective protective preparation against irradiation by short UV sunburn wavelengths (smaller than 320 nm) was found to be a mixture of 5% para-aminobenzoic acid and 2.5% of the ester amyl dimethylaminobenzoate in 70% ethanol with para-aminobenzoic acid being usually more effective than the ester, and mexenone the least effective individually. The protective capacity was found to be reduced by showering but not by exercise. The addition of glycerol to the formulations did not affect their protective capacity although the addition of propylene glycol did increase the protection obtained.