DRUGS OF THE PROLONGED ACTION (synonym: dyurantny drugs; drugs of the prolonged action) — the medicines providing longer therapeutic action but to comparison with the usual drugs containing the same pharmaceuticals. The principle of their action consists in gradual release of certain doses of pharmaceuticals for a long time thanks to what their optimum concentration in an organism is maintained.
Increase in time of stay of medicine in an organism is reached by delay of absorption, biotransformation and allocation. Prolongation of effect of the medicines applied to injections can be carried out by creation of almost insoluble salts, ethers and complex compounds of medicines (e.g., novocainic salt of benzylpenicillin, protamin-tsinkinsulin, ethers of steroid hormones, etc.).
Absorption of medicine from injection solution depends also on viscosity of the last. Use as solvents for injection r-a ditch of vegetable oils with addition of wax and aluminum stearate is based on this principle. Increase in viscosity of solvent can be reached by addition to water solutions of high-molecular compounds (a dextran, polyvinylpirrolidone, carboxymethylcellulose, gelatin). Very absorption of injection drugs in the form of microcrystallic suspensions is considerably slowed down. So, microcrystallic suspension of insulin provides duration of effect of this hormone to the 36th hour. Oil solutions of almost insoluble substances and suspensions enter intramusculary. On site injections of such drugs the depot of medicine from where it is gradually soaked up in blood that provides increase in duration of action is created.
In Ophthalmolum. to practice as Pct of apply solutions of Pilocarpinum of a hydrochloride, Scopolaminum of hydrobromide and homatropine of hydrobromide with methyl cellulose.
Pct of for intake release in the form of microcapsules, spansules, medul, the varnished granulate, impregnirovanny tablets with covers, «duplex» tablets, multilayer tablets. Contained in these dosage forms (see) substance it can be released through certain time irrespective of localization of drug in went. - kish. a path or in the set its department. Some tablets contain two or more single drug doses, each of which is released consistently. At the same time release of the subsequent dose begins at the moment when concentration of substance in blood from the previous dose begins to decrease.
The special dosage form with the prolonged type of action is represented by implantation tablets and sterile capsules which implant in the operational way under skin. This way of introduction of drugs provides uniform receipt them in blood and action within several months. In such dosage forms produce some hormonal drugs and means applied to treatment of alcoholism (e.g., Teturamum).
Ointments and suppositories on special bases, suppository with covers, rectal tampons belong to soft dosage forms with the prolonged action. Prolongation of effect of medicine can be received also for the account pharmakol. interactions with other substances, e.g. use of adrenaline with mestnoanesteziruyushchy means prolongs pharmakol. effect of the last.
See also Pharmaceuticals .
Bibliography: I. A. Tekhnologiya's ants of drugs, t. 1 — 2, M., 1980; Voigt R. Lehrbuch der pharmazeutischen Technologie, S. 721, B., 1973.
C. I. Zolotukhin, V. F. Kremneva.