From Big Medical Encyclopedia

BIOPHARMACY — the direction in pharmacy studying influence of physical and chemical properties, a dosage form and technology of preparation of drugs on biological effect of medicinal substances. Arose at a boundary 50 — the 60th years of the current century.

B. considers medicine as difficult physical. - the chemical system interacting with biol, systems. On intensity of absorption and metabolism of medicinal substances considerable impact is exerted so-called pharm. factors: the nature and amount of the aids used at their production, a dosage form, the nature of technological operations physical. condition of drug.

Aids represent big group of the natural and synthetic compounds which were considered a long time from the point of view of their indifference concerning a macroorganism, form-building properties and a possibility of use for receiving this or that dosage form, the most convenient both for reception, and for storage. As a result of numerous researches it is established that aids can enter interaction with the operating ingredients, significantly influencing their activity. Therefore use of any aid demands carrying out special researches for examination not only its influence on processing behavior of the ingredients entering medicine, but also on processes of absorption, the nature of distribution in an organism and elimination of medicinal substance.

With development of analytical methods of definition of medicinal substances in biol, liquids there was a possibility of obtaining the exact quantitative data indicating dependence of speed of absorption of medicinal substances, their concentration in biol, liquids and the nature of distribution in fabrics and bodies from a dosage form. According to modern representations, the dosage form influences a certain process in an organism not only active agent, but also all set of properties and can be considered as a base unit pharmacotherapy (see). Studying of the difficult, realized via various mechanisms nature of this influence will allow to increase considerably efficiency of medicine and to reduce the possible undesirable phenomena.

Efficiency of drugs is influenced significantly by various production factors: equipment, technological operations, pressure, type of energy, etc. So, the size of pressure used during the pressing of tablets influences time of their raspadeniye and speed of dissolution of active ingredients. Granulation (especially wet) can cause the slowed-down absorption of drug. Quantity of the wetting liquid applied at granulation the size and a form of granules, diameter of tablets significantly influence on fiziol, availability of the tableted drugs. The attention of researchers is concentrated on comparative study of the technological processes and production factors for the purpose of the choice of the most optimum providing therapeutic activity and equivalence of drugs (clinical compliance of the drugs identical on chemical structure, in the same dose and a dosage form).

Physical. the condition of medicinal substance is characterized by hl. obr. extent of its crushing, crystal structure (existence of polymorphism) and solubility. It is established, e.g., that the speed and extent of its absorption, concentration and time of stay in an organism substantially depend on the size of its particles. Data of this dependence for many sulfanamide drugs, antibiotics, derivatives of coumarin are obtained.

The same medicinal substance in a crystalline and amorphous state possesses various action spectrum. Considerable experimental material confirms influence of structure of a crystal on activity of medicinal substance.

In a crust, time a significant amount of polymorphic forms of steroids, streptocides, barbiturates is studied.

At evaluation test of drugs the great value is attached to their solubility. Well soluble substances are quicker released from dosage forms, diffuse to the place of absorption easier, show quicker to lay down. action. However low solubility medicinal substances are more suitable for prolongation of action.

Essentially new approach to pharm. to factors (proprietary medicine is considered as a difficult complex of the interconnected components which are in total influencing efficiency of medicinal substance) will promote improvement of methods of pharmacotherapy. In each separate case at production of medicinal substance depending on its properties aids, methods of production, a dosage form etc. taking into account their influence on activity and side effect of drug shall be picked up.

The new interpretation of drugs and methods of assessment of their quality do not exclude former methods and standards which are considered as the methods defining commodity properties of drugs.

See also Pharmacy .

Bibliography: Tentsova A. I. and Azhgi-h and I. S N. Dosage forms and therapeutic effectiveness of drugs, M., 1974; Wagner J. G. Biopharmaceu-tics and relevant pharmacokinetics, Philadelphia, 1971, bibliogr.

A. I. Tentsova.