Seiss, Mario and Nitz, Siegfried and Kleinsasser, Norbert and Buters, Jeroen T. M. and Behrendt, Heidrun and Hickel, Reinhard and Reichl, Franz X. (2007) Identification of 2,3-epoxymethacrylic acid as an intermediate in the metabolism of dental materials in human liver microsomes. DENTAL MATERIALS, 23 (1). pp. 9-16. ISSN 0109-5641,
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Objectives. In previous studies it could be demonstrated that methacrylic acid (MA) is an intermediate in the metabolism of unpolymerized dental comonomers, released from dental restorative materials. This study was performed to identify the possible dental material intermediate 2,3-epoxymethacrylic acid (2,3-EMA) from MA in human liver microsomes. Most epoxy compounds are regarded as highly toxic substances. Methods. The formation and hydrolysis were studied in defined systems containing only MA and human liver microsomes at 37 degrees C. Hydrolysis was inhibited by cyclohexene oxide, a competitive inhibitor of epoxide hydrolase. The reaction product 2,3-EMA was analyzed by the headspace gas chromatography-mass spectrometry. After 5, 30, and 60 min samples were taken and analyzed. Results. For the reaction of MA to 2,3-EMA the average conversion rate was about 5% within 1 h. It was found that without cyclohexene oxide the rate constant of enzymatic hydrolysis at pH 7.4 was about 10 times higher than the rate constant of the formation from MA in combination with cyclohexene oxide (k = 8.3 versus 0.83 mu mol/l min), indicating an instability and thus a high reactivity of 2,3-EMA. The formation of the MA intermediate 2,3-EMA was not observed when heat-inactivated liver microsomes were used (controls). Significance. It could be clearly demonstrated that 2,3-EMA is a product of dental material metabolisms in biological systems. Therefore, increased toxicity might occur on dental restorative materials which are able to release (co)monomers which can be metabolized to MA. (C) 2005 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | IN-VITRO METABOLISM; GUINEA-PIGS; SALMONELLA-TYPHIMURIUM; BIOLOGICAL CLEARANCE; SPECIES-DIFFERENCES; MUTAGENIC-ACTIVITY; EPOXIDE HYDROLASE; V79 CELLS; GLUTATHIONE; CYTOCHROME-P450; methacrylic acid; 2,3-epoxymethacrylic acid; human liver microsomes; metabolism |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Hals-Nasen-Ohren-Heilkunde |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 12 Jan 2021 06:04 |
| Last Modified: | 12 Jan 2021 06:04 |
| URI: | https://pred.uni-regensburg.de/id/eprint/33395 |
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