Multi-dimensional in vitro bioactivity profiling for grouping of glycol ethers.

High-content screening data derived from physiologically-relevant in vitro models promise to improve confidence in data-integrative groupings for read-across in human health safety assessments. The biological data-based read-across concept is especially applicable to bioactive chemicals with defined mechanisms of toxicity; however, the challenge of data-derived groupings for chemicals that are associated with little or no bioactivity has not been explored. In this study, we apply a suite of organotypic and population-based in vitro models for comprehensive bioactivity profiling of twenty E-Series and P-Series glycol ethers, solvents with a broad variation in toxicity ranging from relatively non-toxic to reproductive and hematopoetic system toxicants. Both E-Series and P-Series glycol ethers elicited cytotoxicity only at high concentrations (mM range) in induced pluripotent stem cell-derived hepatocytes and cardiomyocytes. Population-variability assessment comprised a study of cytotoxicity in 94 human lymphoblast cell lines from 9 populations and revealed differences in inter-individual variability across glycol ethers, but did not indicate population-specific effects. Data derived from various phenotypic and transcriptomic assays revealed consistent bioactivity trends between both cardiomyocytes and hepatocytes, indicating a more universal, rather than cell-type specific mode-of-action for the tested glycol ethers in vitro. In vitro bioactivity-based similarity assessment using Toxicological Priority Index (ToxPi) showed that glycol ethers group according to their alcohol chain length, longer chains were associated with increased bioactivity. While overall in vitro bioactivity profiles did not correlate with in vivo toxicity data on glycol ethers, in vitro bioactivity of E-series glycol ethers were indicative of and correlated with in vivo irritation scores.

Remarkable effect of 2,2'-bipyridyl: mild and highly chemoselective deprotection of methoxymethyl (MOM) ethers in combination with TMSOTf (TESOTf)-2,2'-bipyridyl.

The remarkable effect of 2,2'-bipyridyl led to the successful development of the mild and highly chemoselective deprotection method of methoxymethyl (MOM) ethers using the combination of TMSOTf (or TESOTf) and 2,2'-bipyridyl; this method can be applied to the direct conversion of the MOM group to other ethereal protective groups (e.g. benzyloxymethyl) with the corresponding alcohols.

Ranking of refrigerants.

Environmental ranking of refrigerants is of need in many instances. The aim is to assess the relative environmental hazard posed by 40 refrigerants, including those used in the past, those presently used, and some proposed substitutes. Ranking is based upon ozone depletion potential, global warming potential, and atmospheric lifetime and is achieved by applying the Hasse diagram technique, a mathematical method that allows us to assess order relationships of chemicals. The refrigerants are divided into 13 classes, of which the chlorofluorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, hydrofluoroethers, and hydrocarbons contain the largest number of single substances. The dominance degree, a method for measuring order relationships among classes, is discussed and applied to the 13 refrigerant classes. The results show that some hydrofluoroethers are as problematic as the hydrofluorocarbons. Hydrocarbons and ammonia are the least problematic refrigerants with respect to the three environmental properties.

The activities of INRS in the classification and labeling of glycol ethers.

Glycol ethers are a complex family of more than 30 substances that exhibit a wide range of toxicological properties. This complexity can lead to confusion over which are of real concern and which do not pose significant hazards. Also, many have not been reviewed under the European hazard classification and labelling scheme. Following a major study carried out in France, a number of glycol ethers were identified for review under the classification scheme. This process is now substantially complete and revised classification proposals made and agreed at the European level. When these changes are enacted, the classification of all the commercially important glycol ethers and glymes will reflect their known toxicological hazards.

Using hydrofluoroether solvents to replace HCFC-141b, Part I.

Hydrochlorofluorocarbon solvents have been used for a variety of applications, including silicone deposition, precision cleaning, drying and tube swelling. Their use in these applications is banned in Europe from the end of 2001. Part I of this article explores the technical merits of replacement solvents, with particular reference to hydrofluoroethers.

Septamycin, a polyether antibiotic. Taxonomy, fermentation, isolation and characterization.

Septamycin is a metal complexing polyether antibiotic produced by a strain of Streptomyces hygroscopicus NRRL 5678. The metabolite, a monocarboxylic acid, was isolated as the sodium salt C48H81NaO16. The crystal structure and absolute configuration were established by X-ray analysis of the p-bromophenacyl derivative. Septamycin has a thirty-carbon backbone and contains seven heterocyclic rings. Supported by direct comparison septamycin proved to be identical with antibiotic A28695 A isolated from Streptomyces albus NRRL 3883. The metabolite is active against gram-positive bacteria and Eimeria tenella (chicken coccidiosis).