Toxic compounds, identification

The development of newer agents continues because it is relatively easy to synthesize chemicals with local anesthetic properties. Unfortunately, it is difficult to reduce the toxicity of these compounds because the common side effects of local anesthetics represent extensions of their therapeutic effects. New research into the mechanisms of local anesthetic-induced cardiac and spinal toxicity and identification of alternative drug targets for spinal analgesia (eg, opioid receptors, [Pg.560]

Identification of noxious or toxic compounds and their quantification in serum and urine from emergency cases. 

As a result, materials for medical devices and drug products must be tested for leachable components. Once a known toxic compound is discovered, it must be identified for the assessment of toxicity, followed by the monitoring of levels using validated methods as required by the FDA. This identification procedure could be a time-consuming process with traditional methods that are based on fractionation and individual component analysis. 

The real risks resulting from the bioavailability and mobility of pollutants to be determined 9.7.1 Identification of Toxic Compounds... 

Detecting and identifying toxic compounds in environmental samples (compounds with unknown structures and properties) require the use of time-consuming, costly methods to isolate them from the matrix, then the application of complex techniques to separate the compounds present in an extract, and finally the determination of their structure (identification). Applying such a procedure to all samples collected from a selected area is very expensive. Samples therefore need to be selected, for example, with the aid of the results of ecotoxicological tests samples with the determined toxicity may contain toxic compounds. 

Farre, M., G. Kloter, M. Petrovic, M.C. Alonso, M.J.L. de Alda, and D. Barcelo. 2002. Identification of toxic compounds in wastewater treatment plants during a field experiment. Anal. Chim Acta 456 19-30. 

Extract samples were divided into fractions for a toxicity assessment and file identification of toxic compounds... 

The evaluation of different chemicals involves identification of potential active agents and the mechanisms by which they present their toxic effect, prediction of effective pharmaceutical cytotoxicity for treatment of patients with cancer, evaluation of the activity range of the studied compound, identification of a target cell population and of the toxic concentration range, and the relation between pharmaceutical concentration and exposure period to reach a desired activity. The chosen assay system should provide a reproducible dose-response curve with low variability over a concentration range that includes in vivo exposure. In addition, the selected response criterion should present a linear relationship with cell number, and the information obtained with a dose-response curve should be related to the in vivo effect of the same active agent or drug. 

The purpose of this symposium was to bring together chemists actively working in the occupational health/industrial hygiene field to review the state of the art of analytical techniques and discuss research on sampling and identification of potentially toxic compounds in the workplace. 

Plants are not different from other natural product samples in that they too tend to interfere with various screening formats in nonspecific ways as nuisance compounds displaying unwanted color, inherent fluorescence, promiscuous or aggregate behaviors, detergent-like activities, or toxicity (Feng et al., 2005 Appleton, Buss, and Butler, 2007). Biochemical assays (cell-free defined systems) are notoriously sensitive to such interference by natural product extracts. Cell-based reporter assays and cell-based so-called phenotypic screens always require parental cell controls to determine extract toxicity. However, plants contain their own sets of components that are problematic to screening assays and compound identification. 

Chemical investigations dealing with the identification of toxic compound(s) responsible for the toxicity of a mussel, Mytilus edulis, from eastern Prince Edward Island, Canada, has resulted in the identification of domdc acid [116] (95). Domoic acid was originally isolated over 30 years ago from the red alga Chondria armata (96). A further investigation of the toxic mussels has resulted (97) in the isolation of domoic acid D [117] and two geometric isomers, isodomoic acid E3 [118] and isodomoic acid E4 [119]. 

Application of the effect-directed analysis methodology has been reviewed. It consists of the search of toxic compounds present in complex samples, such as those stemming from the environment and industrial effluents, following the simplification operations shown in equation 4, where BA = biological assay, CA = chemical analysis and FR = fractionation. At present it is too expensive for screening applications however, it is amply justified for identification of specific toxicants near the source of emission, as was the case of mutagens in Table 2.D in river waters84. 

Ecotoxicity tests react to the presence of a wide range of toxic substances, therefore suitable for the overall evaluation of the ecological status of waters. However, not sensitive enough in comparison with laboratory techniques, and just as the above mentioned biosensor, not applicable for the identification of the toxic compounds and... 

Recently, LC-MS techniques have become increasingly popular as an approach to analytical problems. In keeping with this development, Saint-Marcoux et al described a general unknown screening procedure for serum samples, using SPE and subsequent liquid chromatography-electrospray mass spectrometry (LC-ESIMS). This method allows for the detection and identification of pesticides and also other drugs and toxic compounds. 

Molecular sieves arc used in various applications in nuclear medicine. For example, small beads of zeolites were soaked in a solution of radioactive ions. These zeolite beads are employed as point source markers for the identification of anatomical landmarks and for gamma camera uniformity. Due to their small size and relatively high uptake they provide excellent devices for measuring spatial resolution, detector unifonnity and energy resolution.[54] Zeolites are also utilized as binding agents for toxic compounds and antioxidant for selenium, vitamins, and provitamins, and arc also used as mineral additive in various dietary strategies.[55]... 

Methods for identification of toxic compounds, including physical symptoms and laboratory methods. 

Plasma emission spectroscopy is an elemental analysis technique that is, it provides no information on the chemical form or oxidation state of the element being determined. The identification of the chemical state of an element in a sample is called speciation. For example, in environmental samples, mercury may exist in a variety of species mercuric ion, mercurous ion, methymercury compounds, and the extremely toxic compound dimethyhnercury. Determination of mercury by ICP-OES results in total mercury concentration chemical speciation would teU us how much mercury is present in each of the different forms. Arsenic is another element of environmental and health interest because of its toxicity. Arsenic, like mercury, exists in multiple organoarsenic compounds and multiple oxidation states as inorganic arsenic ions. Why is speciation... 

Polycyclic organic matter, derived from the total exhaust emission, is an extremely complex mixture. It includes a large number of compounds such as polynuclear aromatic hydrocarbons (PAH), derivations of PAH such as nitro-PAH and amino-PAH, oxygenated PAH such as phenols and quinones, and heterocyclic aromatic compounds containing sulfur and oxygen. In order to assist in the identification of classes of toxic compounds it is possible to fractionate the exhaust emissions into vapor and... 

Comparison of measured data on acute toxicity with calculated baseline predictions revealed that 21.5% of the compounds (53 out of 246) were at least five times more toxic towards Daphnia than estimated, whereas almost 80% had non-specific toxicity. The identification of potential outliers from the baseline QSAR models based on the set of reactive substructures derived from fish tests (section 5.1) is only partly satisfactory 19 outliers (35.8%) were recognized from their substructures and seven baseline toxicants (3.6%) were incorrectly assumed to exert excess toxicity (Jackel and Nendza, 1994). Those compounds with reactive substructures actually show excess toxicity towards Daphnia, but not all outliers are recognized. Accordingly, the set of indicators devised for fish has to be adjusted to cover different modes of action on specific targets in different organisms. 

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