Impurities toxic

Impurities Toxicity not a major issue May impact immunogenicity May be significant Purity standards well established... 

In addition to the above, the United States Pharmacopeia (USP) addresses impurities using additional terminology 4 foreign substances and other impurities, toxic impurities, and ordinary impurities. 

Toxicity and immunogenicity of CNTs in vivo and in vitro studies has been attributed to various factors such as number of walls, length and aspect ratio, surface area, degree of aggregation, extent of oxidation, hydrophobicity, surface topology, method of administration, dispersibility, type and degree of functionalization, and method of manufacture (which can leave catalyst residues and produce impurities). Toxicity of CNTs is also dependent on their concentration, dose, duration and method that cells or organisms are exposed to them and even the utilized dispersant to solubilize the nanotubes. 

Waste Treatment. Environmental concerns have increased the need to treat Hquid discharges from all types of industrial processes, as well as mnoffs where toxic substances appear as a result of leaks or following solubilization (see Wastes, industrial). One method of treatment consists of an ion-exchange system to remove the objectionable components only. Another involves complete or partial elimination of Hquid discharges by recycling streams within the plant. This method is unacceptable unless a cycHc increase in the impurities is eliminated by removing all constituents prior to recycling. 

Chemical fertiliser is the predominant market for langbeinite. Comparatively small but increasing amounts of langbeinite are used by the animal feed ingredient industry (see Feeds and feed additives). Producers who supply this market must take special precautions to be sure that any langbeinite intended as an animal feed ingredient meets all USDA specifications for toxic heavy metals and other impurities. 

Clinical studies with streptovaricins have been Umited. The most significant toxicity reported in the clinical studies has been gastrointestinal disturbances. However, indications are that the toxicity does not result from the individual streptovaricins but from some impurity in some fermentation lots (85). 

Impurities. The presence of impurities may modify the toxic response, particularly if they have high toxicity. 

Nonmolecular species, including radiant quanta, electrons, holes, and phonons, may interact with the molecular environment. In some cases, the electronic environment (3), in a film for example, may be improved by doping with impurities (4). Contamination by undesirable species must at the same time be limited. In general, depending primarily on temperature, molecular transport occurs in and between phases (5), but it is unlikely that the concentration ratios of molecular species is uniform from one phase to another or that, within one phase, all partial concentrations or their ratios are uniform. Molecular concentrations and species that are anathema in one appHcation may be tolerable or even desirable in another. Toxic and other types of dangerous gases are handled or generated in vacuum systems. Safety procedures have been discussed (6,7). 

Polychlorophenoxyphenols are the principal impurity in mixtures of tetrachlorophenols and pentachlorophenols. Traces of polychlorodibenzoparadioxins and polychlorodibenzofurans can also be present if the chlorination is not conducted correctiy. 2,3,7,8-Tetrachlorodibenzoparadioxia [1746-01 -6] which is highly toxic, has never been detected in any products derived by chlorination. 

For enzymes intended for parenteral use, the manufacturer must assure that the enzyme preparation is essentially pure and free of endotoxins. Electrophoretic and immunologic tests provide the requisite evidence of purity and homogeneity. Most importandy, the manufacturer must remove toxic impurities, eg, bacterial hpopolysacchati.de (endotoxins) which might cause severe toxic reactions such as anaphylactic shock, fever, and vascular coUapse. 

NOVEL EXPRESS METHODS FOR OUTDOOR RAPID DETECTION OF TOXIC IMPURITIES IN ENVIRONMENT AND SOCIALLY INSECURE PHARMACOLOGICAL SUBSTANCES... 

Ailyl chloride [107-05-1] M 76.5, b 45.1", d 0.939, n 1.4130. Likely impurities include 2-chloropropene, propyl chloride, /-propyl chloride, 3,3-dichloropropane, 1,2-dichloropropane and 1,3-dichloropropane. Purified by washing with cone HCl, then with Na2C03 soln, drying with CaCl2, and distn through an efficient column [Oae and Vanderwerf J Am Chem Soc 75 2724 1953], LACHRYMATOR, TOXIC. 

Propargyl chloride (3-chloropropyne) [624-65-7] M 74,5, b 58 /760mm, 65 /760mm, d 1.03, n 1.435. Purified by fractional distn at atm press. Note that a possible impurity propargyl alcohol has b 114-115°/atm. [Henry Chem BerS 398 1 875.] HIGHLY TOXIC and FLAMMABLE. 

Carbonyl bromide/595-95-iy M 187.8, b 64.5°/760mm. Purified by distn from Hg and from powdered Sb to remove free bromine, then vacuum distd to remove volatile SO2 (the major impurity) [Carpenter et al. y Chem Soc. Faraday Trans 2 384 1977]. TOXIC... 

The disposal of waste oils is largely governed in the UK by the EPA 90. Waste oils are a Special Waste covered by Special Waste Regulations. Establishments handling more than 500 litres per annum have a duty to maintain records. There are also requirements for record keeping where waste oils contain toxic impurities and so become Special Waste . 

---