Mexenone's 48-hour LC50 against D. japonica's LC50 against D is 1.5 mg/L. Ecosar's magnaby is 0.9 mg/L [1].

Toxicity Summary
IDENTIFICATION AND USE: 2-Hydroxy-4-methoxy-4'-methylbenzophenone (Mexenone) belongs to the benzophenone group of sunscreens. HUMAN STUDIES: Mexenone was reported as one of the most frequent contact allergens among other sunscreen agents. The benzophenone group of sunscreens (mexenone, oxybenzone) were the most frequent sensitizers, accounting for 8 of the 27 positive patch tests observed for a sunscreen agents. It has also produced positive responses in photopatch testing. A case report described a patient with long-standing polymorphic light eruption who developed a photocontact allergy to mexenone and several contact allergies. ANIMAL STUDIES: There are no data available.

---

Interactions
OBJECTIVE: To describe and identify the photoallergens causing photoallergic contact dermatitis in the population attending the outpatient clinic of the Centro Dermatologico Federico Lleras Acosta (CDFLLA), the National Institute of Dermatology of Colombia. MATERIALS AND METHODS: Eighty-two patients with clinical diagnosis of photoallergic contact dermatitis enter the study. These patients attended the CDFLLA between August 2001 and May 2003. Photopatch tests were performed using the standard series of sunscreens (Chemotechnique Diagnostics) and 6-methylcoumarin. Cetyl alcohol, phenoxyethanol, methylparabene, propylene glycol, triethanolamine, propylparabene, trichlorocarbanilide and dichromate were also included. The allergens were applied in duplicate on the healthy skin of the back and covered with opaque tape withdrawn 24 hr later, the panel on the right was irradiated with an ultraviolet A dose of 5 J/cm(2). The tests were read 24 h after the application of the allergens, 24 and 72 hr post-irradiation. The readings were assessed according to the visual scoring system recommended by the International Contact Dermatitis Research Group. RESULTS: Twenty-six patients (31.7%) showed positive photopatch test responses to one or several allergens. Four of them showed positive results to three components of the series and four patients to two components. Thirty-eight photoallergic and 18 allergic reactions were observed. Ultraviolet filters were the substances which more frequently produced positive photopatch test responses (30.5%). The most common ultraviolet filter photoallergen was benzophenone-3 with 22/82 positive results (26.8%), followed by octyl methoxycinnamate (8/82), benzophenone-4 and mexenone (2/82), phenylbenzimidazole sulphonic acid, methylbenziliden camphor and octyl dimethyl PABA (1/82). One patient showed a photoallergic response to 6-methylcoumarin. There was a concordance between the allergen which elicited the positive response and the use of different substances which contained that molecule among its compounds in 17 patients (65.3%). 19.5% of the patients (16/82) showed positive results to one or several allergens in the irradiated panel as well as in the unirradiated control site. These cases were diagnosed as contact allergy, probably caused by aeroallergens, presenting a natural history and a clinical picture similar to photocontact allergy. The most common allergen was dichromate with 10 positive results. CONCLUSIONS: The results of this study confirm that sunscreens are the more frequently involved substances in photoallergic contact dermatitis in our population. Identification of the photoallergen is the key element for adequate disease control and patient education.
INTRODUCTION: Between September 1994 and September 1999, we observed 19 cases of photoaggraved contact allergy or contact photoallergy to ketoprofen (non steroidal anti-inflammatory derived from arylpropionic acid). We present a clinical and photobiological retrospective study of these 19 cases with investigation of cross-reactivity between benzophenone-containing molecules. PATIENTS AND METHODS: On clinical level, we investigated the type of eruption, the delay of appearance, the initial area of eruption and areas of diffusion. Phototesting included patchtests and photopatchtests performed with the gel containing ketoprofen (17 patients), ketoprofen 2 p. 100 petrolatum (14 patients), fenofibrate 10 p. 100 petrolatum and 10 p. 100 water (15 patients), 3 benzophenones (19 patients): oxybenzone 10 p. 100 petrolatum, mexenone 2 p. 100 petrolatum, sulisobenzone 10 p. 100 petrolatum and the other arylpropionic derivatives (4 patients). Three identical series were applied: one was irradiated with 3/4 polychromatic minimal erythematosus dose, a second was irradiated with UVA 13 J/cm2 until January 1997, then 5 J/cm2, the third series was not irradiated (control series). RESULTS: Patients were 9 men and 10 women with an average age of 41.2 years. The type of eruption was an eczema. The delay of appearance of the eruption was one day to 3 months. For 10 patients, the delay was between 4 and 18 days. The eruption was localized to the application area in 1 case, to the application area then to the same contralateral area in 3 cases, to the application area then to all photoexposed areas in 13 cases, to the application area then to the photoexposed areas and then to non-sun-exposed areas in 2 cases. Evolution showed prolonged photosensitivity in 3 cases after withdrawal of the contact and the contact photoallergy to ketoprofen was severe. Gel-containing ketoprofen photopatchtests showed 9 photoaggravated contact allergy, 6 contact photoallergy and 2 contact allergy. Ketoprofen photopatchtests showed 12 contact photoallergy and 2 photoaggraved contact allergy. Tiaprofenic acid photopatchtests were positive in all performed cases (4/4), but photopatchtests with the other arylpropionic derivatives, without benzophenone structure, were negative. Fenofibrate photopatchtests were always positive (15/15). Benzophenones photopatchtests only showed 4 cases of contact photoallergy to oxybenzone (4/19). In 68 p. 100 of cases, patients presented a contact allergy or photoallergy to fragrances. CONCLUSIONS: This study shows the actual frequency of contact allergy and contact photoallergy to ketoprofen with a higher frequency of contact photoallergy. Thus, photopatchtesting is essential. In cases of contact photoallergy to ketoprofen, ketoprofen, tiaprofenic acid but not the other arylpropionic derivatives, fenofibrate and benzophenones have to be withdrawn.

[1]. Acute toxicity of benzophenone-type UV filters and paraben preservatives to freshwater planarian, Dugesia japonica. Toxicological & Environmental Chemistry. Volume 94, 2012 - Issue 3.

Mexenone is a member of benzophenones.

C15H14O3

242.26986

242.094

1641-17-4

71645

Light yellow to yellow solid powder

1.2±0.1 g/cm3

400.1±35.0 °C at 760 mmHg

99-102°C

150.2±19.4 °C

0.0±1.0 mmHg at 25°C

1.588

4.1

1

3

3

18

282

0

MJVGBKJNTFCUJM-UHFFFAOYSA-N

InChI=1S/C15H14O3/c1-10-3-5-11(6-4-10)15(17)13-8-7-12(18-2)9-14(13)16/h3-9,16H,1-2H3

(2-hydroxy-4-methoxyphenyl)-(4-methylphenyl)methanone

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~50 mg/mL (~206.38 mM)
H2O : < 0.1 mg/mL

Solubility in Formulation 1: 2.5 mg/mL (10.32 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (10.32 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

 (Please use freshly prepared in vivo formulations for optimal results.)