ASTRINGENTS (Adstringentia) — the medicinal substances causing at direct contact with fabrics and liquids of an organism their consolidation or formation of insoluble compounds in the form of a dense protective film.
V.'s action by the village is based on physical. - chemical processes: reacting with fabric elements, V. villages take away water (dehydration) and by that increase viscosity and density of proteins in fluid mediums and fabrics or enter chemical reactions, forming the connections (e.g., albuminates) which are dropping out in a deposit and covering with a thin coat a surface of a wound or ulcer; the formed film changes a current fiziol. and biochemical, processes on site inflammations. Condensing a surface layer of fabrics, V. pages reduce an exit of liquid from small circulatory and limf, vessels, narrow their gleam and detain an exit of uniform elements through the condensed wall of vessels; at the same time the hyperemia disappears, decrease or completely secretory processes stop. As a result of wrinkling or squeezing of cells their size and volume decreases, the irritating influence of external factors and absorption of bacteria is sharply limited. Changing a current biochemical, processes in a wound or on site inflammations, V. pages violate living conditions of bacteria and thus reduce their life activity, complicate reproduction, reduce formation of toxins; in some cases have direct pernicious effect on them. Under the influence of V. pages decrease or completely pains both related difficult reflex and biochemical disappear, -
V. pages divide the phenomena (formation of histamine-like substances, etc.) into two groups: organic and inorganic.
To organic V. of page. hl belong. obr. the tanning agents which are contained in various parts of plants (wood, bark, leaves, a root, a rhizome and fruits). In medicine use Gallae turcicae, bark of an oak (Cortex Quercus), a sage (Salvia officinalis), a coil (Polygonum bistorta), a ptarmigan-berry [Arctostaphylos uva ursi], bilberry and other plants containing tanning agents (see. Medicinal plants ). These substances have no resorptive effect. In went. - kish. a path they quickly collapse (especially in alkaline condition) therefore at inflammatory processes in intestines it is better to apply Tannalbinum (see).
Processes of transformation of tanning agents in an organism are still a little studied.
To inorganic B. of page. salts of metals — drugs belong aluminum (see), bismuth (see), gland (see), calcium (see), copper (see), lead (see), silver (see), zinc (see), etc. Effect of salts of metals is based on sedimentation of proteins and formation of albuminates (compound of proteins with metals). In weak concentration (to 1%) salts of metals have the knitting effect and are applied as anti-inflammatory drugs, in higher (1 — 5%) — irritant action, and in big concentration (from 5 to 10%) — cauterizing. Extent of the antiinflammatory and cauterizing effect of salts of metals on fabric depends on properties of albuminates — their solubilities in water, tissue juices, excess of protein and a precipitator; their physical. states (dense, friable); character of the acid which is formed as a result of eliminating from metal salt (organic or inorganic, high or low extent of its dissociation, etc.); solubilities and concentration of metal salt, its dehydrational properties; duration of purpose of drug and properties of fabric, etc. On degree of solubility of the formed albuminates metals it is possible to arrange in the following order: Ph, Fe, Bi, Al, Zn, Cu, Tl, Au, Ag... Hg. The albuminates formed by the metals located to the left from Cu are slightly soluble, give dense educations and have, as a rule, antiinflammatory properties; the metals located on the right, especially mercury have the cauterizing effect.
Century of page apply locally at various inflammatory processes on mucous membranes and skin, sometimes as the styptic and deodorizing means. Drugs, calciferous, have antiinflammatory effect at introduction to blood. Salts of metals use also for cauterization of granulations and new growths.
At absorption in blood of salt of metals (e.g., lead, mercury, etc.) can cause heavy poisonings (see).
Bibliography: Mashkovsky M. D. Pharmaceuticals, t. 1, with 262, M., 1972; The Guide to pharmacology, under the editorship of N. V. Lazarev, t. 2, page 84, L., 1961.