In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a given substance. The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indicative of higher toxicity.
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ such as the liver (hepatotoxicity). Sometimes the word is more or less synonymous with poisoning in everyday usage.
Acute toxicity describes the adverse effects of a substance that result either from a single exposure or from multiple exposures in a short period of time. To be described as acute toxicity, the adverse effects should occur within 14 days of the administration of the substance.
Oxygen difluoride is a chemical compound with the formula OF2. As predicted by VSEPR theory, the molecule adopts a bent molecular geometry. It is a strong oxidizer and has attracted attention in rocketry for this reason. With a boiling point of −144.75 °C, OF2 is the most volatile (isolable) triatomic compound. The compound is one of many known oxygen fluorides.
p-Xylene (para-xylene) is an aromatic hydrocarbon. It is one of the three isomers of dimethylbenzene known collectively as xylenes. The p- stands for para-, indicating that the two methyl groups in p-xylene occupy the diametrically opposite substituent positions 1 and 4. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and m-xylene. All have the same chemical formula C6H4(CH3)2. All xylene isomers are colorless and highly flammable. The odor threshold of p-xylene is 0.62 parts per million (ppm).
Cadmium telluride (CdTe) is a stable crystalline compound formed from cadmium and tellurium. It is mainly used as the semiconducting material in cadmium telluride photovoltaics and an infrared optical window. It is usually sandwiched with cadmium sulfide to form a p–n junction solar PV cell.
Copper(II) fluoride is an inorganic compound with the chemical formula CuF2. The anhydrous form is a white, ionic, crystalline, hygroscopic salt with a distorted rutile-type crystal structure, similar to other fluorides of chemical formulae MF2 (where M is a metal). The dihydrate, CuF2·2H2O, is blue in colour.
Methoprene is a juvenile hormone (JH) analog which acts as a growth regulator when used as an insecticide. It is an amber-colored liquid with a faint fruity odor.
The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is an internationally agreed-upon standard managed by the United Nations that was set up to replace the assortment of hazardous material classification and labelling schemes previously used around the world. Core elements of the GHS include standardized hazard testing criteria, universal warning pictograms, and safety data sheets which provide users of dangerous goods relevant information with consistent organization. The system acts as a complement to the UN numbered system of regulated hazardous material transport. Implementation is managed through the UN Secretariat. Although adoption has taken time, as of 2017, the system has been enacted to significant extents in most major countries of the world. This includes the European Union, which has implemented the United Nations' GHS into EU law as the CLP Regulation, and United States Occupational Safety and Health Administration standards.
A dichlorodifluoroethylene is one of three compounds with the chemical formula C
2Cl
2F
2. Dichlorodifluoroethylenes are colourless gases, and are some of the simplest chlorodifluoroalkenes.
Sulfacetamide is a sulfonamide antibiotic commonly used in the treatment of bacterial infections, particularly those affecting the eyes and skin. It functions by inhibiting the synthesis of folic acid in bacteria, which is essential for their growth and reproduction, thereby exerting a bacteriostatic effect. Available in various forms, including eye drops, topical solutions, and creams, sulfacetamide is often prescribed for conditions such as conjunctivitis, seborrheic dermatitis, and acne vulgaris. Its efficacy, coupled with a relatively low risk of side effects, makes it a widely utilized agent in both ophthalmic and dermatologic care.
Persin is a fungicidal toxin present in the avocado. Persin is an oil-soluble compound structurally similar to a fatty acid, a colourless oil, and it leaches into the body of the fruit from the seeds.
Chlorobutanol (trichloro-2-methyl-2-propanol) is an organic compound with the formula CCl3C(OH)(CH3)2. The compound is an example of a chlorohydrin. The compound is a preservative, sedative, hypnotic and weak local anesthetic similar in nature to chloral hydrate. It has antibacterial and antifungal properties. Chlorobutanol is typically used at a concentration of 0.5% where it lends long term stability to multi-ingredient formulations. However, it retains antimicrobial activity at 0.05% in water. Chlorobutanol has been used in anesthesia and euthanasia of invertebrates and fishes. It is a white, volatile solid with a camphor-like odor.
Potassium lactate is a compound with formula KC3H5O3. It is the potassium salt of lactic acid and appears as a clear, hygroscopic, syrupy liquid suspension that is typically 60% solids. The substance can be concentrated to contain up to 78% solids. It is produced by neutralizing lactic acid, which is fermented from a sugar source. It has E number E326.
Polypeptide antibiotics are a chemically diverse class of anti-infective and antitumor antibiotics containing non-protein polypeptide chains. Examples of this class include actinomycin, bacitracin, colistin, and polymyxin B. Actinomycin-D has found use in cancer chemotherapy. Most other polypeptide antibiotics are too toxic for systemic administration, but can safely be administered topically to the skin as an antiseptic for shallow cuts and abrasions.
Daphnin is a plant toxin with the chemical formula C15H16O9 and is one of the active compounds present in the Eurasian and North African genus Daphne of the Thymelaeaceae, a plant family with a predominantly Southern Hemisphere distribution with concentrations in Australia and tropical Africa.
Pregnenolone acetate, also known as pregn-5-en-3β-ol-20-one 3β-acetate, is a synthetic pregnane steroid and an ester of pregnenolone which is described as a glucocorticoid and as a skin-conditioning and skin anti-aging agent. It has been reported to reduce wrinkles in elderly women when applied in the form of a 0.5% topical cream, effects which were suggested to be due to improved hydration of the skin. Pregnenolone acetate has been marketed in France in a topical cream containing 1% pregnenolone acetate and 10% "sex hormone" for the treatment of premature skin aging but was withdrawn from the market in 1992. Although the medication has been described by some sources as a glucocorticoid, other authors have stated that systemic pregnenolone acetate has no undesirable metabolic or toxic effects even at high doses.
Dipropyltin dichloride is an organotin compound with the chemical formula (CH3CH2CH2)2SnCl2. It is a white solid. This chemical belongs to a subclass of organotin compounds called diorganotin dihalides.
S,S'-Dimethyl dithiocarbonate is an organic compound with the chemical formula OC(SCH3)2. It is a colorless liquid. It is a methyl ester of dithiocarbonic S,S-acid. It is a thioester. It is an analog of dimethyl carbonate, where the two oxygen atoms from the −OCH3 groups are replaced by sulfur atoms. In terms of the name of this thioester, it is derived from an esterification of dithiocarbonic S,S-acid with methanethiol.
Choline bitartrate is an organic compound with the chemical formula [(CH3)3NCH2CH2OH]+HOOC−CH(OH)−CH(OH)−COO−. It is a white crystalline powder with an acid taste. It is hygroscopic when exposed to air. Modern texts refer to the choline salt of the natural form of tartaric acid, that is, the salt called choline dextrobitartrate, choline (2R,3R)-bitartrate or choline L-(+)-bitartrate.
