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In‐Vitro Stability, Metabolism, and Transport of Dental Monomers Made from Bisphenol A and Bisphenol F
Author(s) -
Burmaster Steve,
Smith Robert,
Eick David,
Kostoryz Elisabet L.,
Yourtee David
Publication year - 2002
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/1616-5195(200211)2:8<365::aid-mabi365>3.0.co;2-l
Subject(s) - chemistry , metabolite , bisphenol a , chromatography , monomer , bisphenol , hydrolysis , bioavailability , biochemistry , organic chemistry , polymer , pharmacology , epoxy , medicine
The stability and bioavailability of the biomaterial monomers, bisglycidyl methacrylate (BISGMA), bisphenol F diglycidyl ether (BFDGE), and bisphenol A dimethacrylate (BPADM) were investigated using in‐vitro techniques. A reverse‐phase high‐pressure liquid chromatographic/mass spectrometric (HPLC/MS) system was developed to quantitate each monomer and its primary metabolite. Each monomer (10 × 10 −6 M ) was incubated at 37 °C under various conditions. Aliquots ( N = 3) were removed at various time intervals and quantitated from a standard curve. The in‐vitro transport of each parent monomer and its tetrahydroxy metabolite was measured in a Caco‐2 system. BISGMA and BPADM were stable in aqueous solution at pH 1. However, BFDGE, was unstable. Plasma esterase of the rat rapidly hydrolyzed the ester compounds, but human esterase did not have a hydrolytic effect on BISGMA or BPADM. BFDGE disappeared in both rat and human plasma, but no tetrahydroxy metabolite was observed. All three parent compounds were unstable in human‐ and rat‐hepatic fractions producing either tetrahydroxy metabolites or bisphenol A (BPA). The tetrahydroxy metabolites, however, were relatively stable under identical conditions, but BPA disappeared when incubated in hepatic‐microsomal fractions. While BPADM metabolism produced BPA, an estrogen disrupter, BISGMA and BFDGE did not appear to produce BPA. These results suggest that the potential toxicity of leached dental monomers is more likely to be a result of the metabolite rather than the parent monomer. From Caco‐2 transport studies, BFDGE and its tetrahydroxy metabolite both crossed the Caco‐2 membrane at a low rate of transport in 2 h (approximately 3 and 5.2%, respectively). The BISGMA metabolite crossed at approximately 8%, indicative of a moderate rate of transport, and BPA crossed at approximately 10% in 1 h (high rate of transport). The transport of BPADM and BISGMA was unable to be determined due to nonspecific absorption to the acrylic vertical transport well. The transport of BFDGE tetrahydroxy metabolite is of particular interest as BFDGE is likely to be chemically hydrolyzed in stomach acid. It is well known that epoxies react with acids resulting in ring opening, so it is not surprising that BFDGE decomposes at pH 1. As a result, it is necessary to identify the decomposition (hydrolysis) products and test their bioavailability.Mean (SD) stability of BISGMA (10 × 10 −6 M ) and bisphenol A tetrahydroxy metabolite in human‐ and rat‐S9‐hepatic fractions at 37 °C for 1 h.