Haber's rule

The Haber's rule is a mathematical relationship used in toxicology between the concentration of a toxic substance and the duration of administration, or exposure of this poison. The Haber's rule is named after the German chemist Fritz Haber, this dose -duration relationship for the first time by the action of toxic gases, including phosgene, aufstellte.

Concentration × time = constant

The Haber's rule states that the product of concentration (C ) and duration ( t) corresponds to a constant (k ) biological effects:

The biological effect may be a disease (eg, cancer), or death of the exposed organism.

In other words, states that Haber's rule that identical products on the concentration and duration of administration lead to the same effect occurs. That is, at constant supply of a subliminal toxic dose toxicity increases with time.

In the diagram ( see Figure 1) with linearly scaled axes results in the hyperbolic curve shape. In contrast, double-logarithmic representation of a straight line.

In the Anglo-Saxon literature, the terms Haber 's Law and Haber 's Rule for the Haber's rule are common.

Examples

Examples of the validity and applicability of Haber's rule are tobacco smoking with lung cancer and the effect of the action of ionizing radiation on body tissues (ultraviolet rays → skin cancer).

Limitations

The Haber's rule is only irreversible effects of summation poisons (also cumulative poisons or c · t poisons called ) such as lead, mercury and all carcinogenic substances applicable. In vital trace elements such as selenium or zinc, the rule fails completely at low concentrations. When concentration poisons, such as carbon dioxide, the Haber rule is also not applicable.