What is the meaning of the semi lethal LD50 in the expression of acute toxicity of hazardous chemica

LD50 refers to the dose of a chemical substance that causes a 50% probability of death in the test animal under certain experimental conditions.

Half lethal dose (LD50) is a rough measure of the acute toxicity of a chemical, and is the dose required to poison half of a group of test animals, and is measured in mg kg.

The half-lethal dose (LD50) of the same test substance for various animals is different, and some even have considerable differences. Depending on the way it is given, the half lethal dose (LD50) is also different. Differences in animal germline, sex, age, and test conditions also affect the half-lethal dose (LD50).

However, compared with the half lethal dose (LD50), it was less affected by the individual differences of animals, and its value was relatively stable and representative. Under different conditions, the half-lethal dose (LD50) of the same test substance still has a certain similar trend, so it can still be compared with each other.

Although humans are different from animals, through the testing of a variety of animals, substances with low toxicity to a variety of animals are generally very low in toxicity to humans. Substances that have a small lethal dose to half of many animals can be considered to be very toxic to humans.

If the dose is greater than 5000mg kg, and the test animal does not die, it means that the acute toxicity is very low, and it can be considered relatively non-toxic, and there is no need to continue to accurately determine the lethal amount. Commonly used calculation methods are the Koehl's method, the unit of probability method, and the Horn method.

The dose of the drug that kills 50 percent of the experimental animals.

LD50 is the acronym for Median Lethal Dose, which specifies the 50% probability of death of the test subject under experimental conditions.

Half lethal dose (LD50): A general rough measure of the acute toxicity of a certain chemical substance, the index refers to the dose required to make half of the test substance poison die, and its unit mg kg is even different from the half lethal dose of various substances of the test substance (LD50). The difference between the giving formula and the half lethal dose (LD50), species, sex, and age test conditions affected the half lethal dose (LD50), while the half lethal dose (LD50) was affected by the difference of objects, and its value was relatively stable and representative. Under the same conditions, the half-lethal dose (LD50) of the tested substance is still determined, and the similar trend is still compared with each other, although the same substance is tested with the same substance, the toxicity of the species is low, and the toxicity of the substance is often low; Half of the lethal amount of the species is considered to be toxic.

If the dose is 5000 mg kg, the test subject does not die, indicating that the acute toxicity is very low, and there is no need to continue to do lethal dose, accurate determination of the lethal dose is used to calculate the Cole, the probability unit Horn formula.

Hazardous chemicals.

The LD50 represents the significance of the acute toxicity: the LD50 that can be determined now is basically the LD50 of animal experiments, that is, the LD50 of animals. And depending on the mode of administration, it should be indicated, such as whether it is oral (oral), subcutaneous (subcutaneous), inhalation (corresponding to LC50 LCT50), intraperitoneal (intraperitoneal), or something else; The type of test animal also needs to be specified, whether it is rat or mouse, dog, or something else.

The unit is g kg, and the next kg is the weight of the test animal. In fact, toxicity and body weight are not necessarily linearly related, but at least within a certain range, this value is still useful. Moreover, this conversion can also roughly estimate the dose of toxicity of the same substance between different animals, and indeed a considerable number of poisons can be used as a reference for the toxicity of this estimated value.

2.Nowadays, the method of calculating LD50 experimentally is called the BLISS method, which itself applies statistical methods to analyze experimental samples.

At the same time, the study of human LD50 is basically through statistical methods, because the sample size is very small, so it can only be used as a simple reference. Toxicology.

There is a conversion method from animal LD50 to human LD50, and in the description of animal toxicity, it is basically more certain, and you can directly write how many mg kg. But the description of toxicity in humans is very imprecise, for example"been estimated to be", or"considered to be about"Wait a minute.

RepresentationHazardous chemicals. The unit of LD50 for acute toxicity is mg kg.

LD50 (lethal dose 50%), which is the half lethal dose (LD is the abbreviation of lethal dose), refers to the dose of poison used to cause half of the experimental animals to die within 14 days after a single poisoning. It is generally expressed in milligrams of poison per kilogram of body weight.

For example, LD50 = indicates that a dose of toxic substance is ingested at one time, resulting in the death of half of the animals tested within 14 days.

Commonly used concentration notations are:

Mass percentage concentration (mass fraction.

m m): most commonly used. Refers to the mass of solute per 100 grams of solution, in grams.

Mass Percentage (solute mass (g)) Solution mass (g)) 100% = solute mass (g)) solute mass (g) + solvent mass (g)) 100%.

Volume percentage concentration (volume fraction.

v v): Commonly used in alcohol. Refers to the volume of solute per 100 ml of solution, in milliliters.

Volume percentage concentration (solute volume (ml) solution volume (ml)) 100% = solute volume (ml) (solute volume (ml) + solvent volume (ml)) 100%.

Parts per million (ppm): Refers to the mass of solute (in milligrams) per kilogram of solution.