Interspecies pharmacokinetic scaling of some iodinated organic acids

We have investigated the possibility of interspecies scaling of relationships between the structure and total plasma clearance in a group of nine organic acids (iododerivatives of benzoic, phenylacetic and hippuric acids) in rabbits, rats and mice. The intercompound comparison established the dependence of total plasma clearance predominantly on the molecular structure in all the animals under study, but the dependence on drug lipophilicity was also meaningful. For interspecies scaling of total plasma clearance, the use of a biological clock with an effective renal plasma flow as the unit seemed most suitable and is probably connected with the principal role of the kidney in the elimination of the compounds under study.     

GC‐MS determination of volatile organic compounds in drinking water supplies in Mexico

Water samples from municipal sources and specific sites in the distribution systems in five Mexican cities were analyzed for 40 volatile organic compounds using a gas chromatograph–mass spectrometer system coupled with a purge‐and‐trap sampler. Benzene and four halogenated compounds, methylene chloride, chloroform, dibromomethane, and dibromochloromethane, were consistently detected in all five cities. Another 20 analytes were identified in some of the 48 sites involved. In many cases, detected concentrations were higher than some internationally accepted drinking water standards. At the time of the study, Mexican regulations did not include values for maximum allowable concentrations levels for volatile organic compounds. From 1996, total trihalomethanes and 10 organochlorine pesticides have been included in Mexican drinking water regulations. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 131–139, 2000     

Studies on iodinated compounds. X. Isolation and purification of iodoglycyltyrosines]

The methods for the isolation and purification of iodoglycyltyrosines [glycyl-3-iodotyrosine (Gly-MIT) and glycyl-3,5-diiodotyrosine (Gly-DIT)] from a reaction mixture were examined by the use of high-performance liquid chromatography (HPLC). Glycyltyrosine (Gly-Tyr) was iodinated with iodine monochloride (ICl) (the molar ratio of Gly-Tyr to ICl was 1:1.5) in 0.1 M NaOH. The synthesized Gly-MIT and Gly-DIT were separated on a mu Bondapak C18 column employing stepwise gradient systems of a 0.1% trifluoroacetic acid/acetonitrile mixture and a water/acetonitrile mixture. Chemically pure Gly-MIT and Gly-DIT were obtained in 30.2% and 28.2% yields, respectively.     

The determination of commonly used iodinated contrast media in postmortem samples using HPLC and TLC

A rapid micro method is described for the determination of diatrizoic, iothalamic, ioxaglic, and iopanoic acids in postmortem liver and blood. The compounds were extracted with methanol and analyzed by high performance liquid chromatography using a C18 column. The mobile phase consisted of methanol:PIC A with ultraviolet detection at 232 and 242 nm. Recoveries of about 85% were obtained. A thin layer chromatographic system is described which separates the four compounds. The spots were hydrolyzed and sprayed with a diazonium coupling reagent to produce colored spots with sensitivities of 0.02 to 0.1 micrograms. Postmortem levels are given for two deaths involving diatrizoic acid.     

Metabolism and effects of organic compounds in animals

In recent years, society has become increasingly aware and concerned about protection from chemicals released into the environment. The knowledge of the metabolism and effects of organic compounds in animals, specifically food-producing animals, are of paramount importance in assessing potential human health hazards. An intensive effort has been directed at detection of chemicals in the environment, determination of their physiological insult and cellular interaction; in particular their carcinogenic and mutagenic induction capability. The chemical exposure of food-producing animals can be extremely difficult to evaluate and quite devastating. The exposure of food-producing animals to polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) emphasizes the seriousness of the problem. The polycyclic aromatic hydrocarbons (PAHs), capable of inducing cancer in experimental animals, have been studied extensively in laboratory animals. Current studies deal with the mechanism of metabolism of PAHs and the ultimate carcinogenic form. Although our knowledge concerning the health hazards of organic chemicals is continually increasing, its impact on food-producing animals and man's food chain is poorly understood. Awareness of the problem by practicing veterinarians and toxicologists, environmental toxicologists and public health officials is required to evaluate the impact of organic chemicals on the human food chain.