title: Biological clearance of HEMA in guinea pigs.
abstract: No toxicokinetic data are available about the dental composite component 2-hydroxyethylmethacrylate (HEMA) in vivo in the literature. Therefore, the excretion of HEMA in feces and urine in vivo and, using the pendular perfusion technique with segments of jejunum and colon, in the biliary and enteric excretion in situ were investigated in anesthetized guinea pigs. In the in situ experiments, guinea pigs (n = 4) received HEMA (0.02 mmol/kgbw labelled with a tracer dose 14C-HEMA 0.3 kBq/gbw) injected into the jugular vein. In the in vivo experiments, guinea pigs (n = 4) received HEMA (+ 14C-HEMA, same dose as above) via gastric tube. Urine and feces were collected for 24h. In the in situ experiments, organs from guinea pigs were removed 60 min after the beginning of the experiment, and then the 14C-radioactivity was measured. During the 60 min perfusion period the calculated amount of 14C-activity excreted into the total jejunum and colon was 6.0 +/- 1.0% and 2.7 +/- 0.7% of the dose administered, respectively (mean +/- sem). Of the 14C-HEMA dose, 5.3 +/- 0.3% was found in the bile. Significantly (p < 0.05) higher bile/blood concentration ratios were found at 10-40 min after the injection of HEMA, as compared to the ratio at 60 min. The total 14C-recovery in all organs tested was 20.0 +/- 2.6%. During 24h the amounts of 14C-activity excreted in the feces and urine were 1.1 +/- 0.1% or 17.1 +/- 1.50% of the dose administered, respectively (mean +/- sem). The total 14C-recovery in all organs tested was 11.6 +/- 0.6%. In a second series of in vivo experiments, exhaled air from the animals was captured during the 24h experimental period. 14C was exhaled to 63.6 +/- 2.11% of the administered 14C-HEMA dose (mean +/- sem; n = 4) as 14C-carbondioxide. The results indicate a rapid clearance of 14C-HEMA and/or 14C-HEMA metabolite(s) from the organism, exhalation being the major route of elimination.
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Germany. reichl@lrz.muenchen.de
authors.forename: F X
authors.initials: FX
authors.lastname: Reichl
authors.forename: J
authors.initials: J
authors.lastname: Durner
authors.forename: J
authors.initials: J
authors.lastname: Manhart
authors.forename: W
authors.initials: W
authors.lastname: Spahl
authors.forename: K
authors.initials: K
authors.lastname: Gempel
authors.forename: K
authors.initials: K
authors.lastname: Kehe
authors.forename: B
authors.initials: B
authors.lastname: Liebl
authors.forename: U I
authors.initials: UI
authors.lastname: Walther
authors.forename: W R
authors.initials: WR
authors.lastname: Hume
authors.forename: R
authors.initials: R
authors.lastname: Hickel
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D008297:Male; D008689:Methacrylates / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D001672:Biocompatible Materials; D002250:Carbon Radioisotopes; D008689:Methacrylates; C005044:hydroxyethyl methacrylate