[Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia].

Sixty-two patients with generalized anxiety disorder (GAD) and neurasthenia were studied. The effect of selank (30 patients) was compared to that of medazepam (32 patients). Patient's state was assessed with psychometric scales (Hamilton, Zung, CGI). Enkephalin activity in the blood serum was measured as well. The anxiolytic effects of both drugs were similar but selank had also antiasthenic and psychostimulant effects. The clinical-biological study revealed that patients with GAD and neurasthenia had the decreased level of tau(1/2) leu-enkephalin which was correlated with disease duration, severity of symptoms related to anxiety and asthenia and autonomic disorders. The increase of this parameter and stronger positive correlations with anxiety level were observed during the treatment with selank mostly in patients with GAD.

Effect of the combination of the benzodiazepine tranquilizer medazepam and the nootropic agent meclofenoxate on the activity of rat brain muscarinic receptors.

1. The effect of 7-day treatment with the benzodiazepine tranquilizer medazepam (5 mg/kg), the nootropic agent meclofenoxate (100 mg/kg) and their combination in the same doses on the binding activity of muscarinic receptors in four rat brain structures (cerebral cortex, striatum, hippocampus and hypothalamus) were studied using the antagonist [3H]-1-quinuclidinyl benzylate [( 3H]-QNB) as radio-ligand. 2. Medazepam treatment caused significant decrease of muscarinic receptor binding affinity (Kd) and of the receptor binding capacity (Bmax) in the brain structures studied. The number of muscarinic binding sites was unsignificantly decreased only in the hippocampus. 3. Meclofenoxate treatment caused an increase of muscarinic receptor affinity and a decrease of the binding capacity in the cerebral cortex and hypothalamus and an increase of the binding affinity in the striatum and hippocampus. 4. The combination of medazepam and meclofenoxate caused no significant changes of both muscarinic receptor characteristics in the hippocampus and of the receptor affinity in the striatum and hypothalamus in comparison with control rats. The Bmax values were decreased in the cerebral cortex, striatum and hypothalamus when compared with control animals. The differences observed were slighter than those determined after the comparison of medazepam treated rats with control rats. 5. The results obtained afford an opportunity to suggest that the nootropic agent meclofenoxate acts to moderate the effect of the benzodiazepine tranquilizer medazepam on the activity of rat brain muscarinic receptors.

[The control of drug release of heavy-soluble, weak basic drugs in matrix tablets using the example of medazepam]. / Zur Steuerung der Arzneistofffreigabe schwerlöslicher, schwach basischer Arzneistoffe aus Matrixtabletten am Beispiel von Medazepam.

According to ideas about the diffusion layer in the process of dissolving solids the release of medazepam as a model substance for heavy-soluble, weak alkaline substances is modified by incorporation of solid acids of different solubility and dissociation rate into the matrix. The determination of the solubility and a "virtual" pH-value within the matrix tablets leads to the evaluation of the liberation. A relatively continuous release of medazepam following different pH-values in the medium was obtained by microencapsulation of the citrus acid incorporated. Using the ideas of the diffusion layer to explain the conditions within the matrix it becomes possible to control and influence the drug release from the matrix tablet.

Effect of diazepam and medazepam on prolactin secretion.

Pharmacological studies of the effect of Diazepam and Medazepam on prolactin secretion were carried out on sexually mature male albino rats. The experiments were carried out using two series of experimental set-ups. In the first series an analysis was made of the effect of Diazepam in doses of 2 and 4 mg/kg body mass, and of Medazepam in doses of 1 and 10 mg/kg body mass, on the prolactin secretion on the 60th min after a single intraperitoneal injection. The second series of experiments was designed to investigate the effect of Diazepam and Medazepam in the same doses under conditions of acute immobilization of the animals for 60 min. The prolactin levels in the serum were tested using a radioimmunological method. Prolactin secretion decreases after a single intraperitoneal administration of Diazepam in both doses. Prolactin content in the serum was reduced only after a dose of 10 mg/kg body mass. Under conditions of experimental immobilization stress, prolactin secretion was stimulated in the animals from the control group, treated with standard solution used as solvent. Diazepam in both doses administered and Medazepam in a dose of 10 mg/kg inhibit the prolactin secretion stimulated by acute immobilization stress.

Plasma concentrations of medazepam and its metabolites after oral administration.

The plasma concentrations of medazepam and its metabolites, diazepam and desmethyldiazepam, were determined in volunteer subjects following the oral administration of medazepam 10 mg. The results indicated that medazepam was absorbed rapidly, that low concentrations of metabolites were present during the 1st h, and that the build-up in the circulation of the major metabolite, desmethyldiazepam, was prolonged and variable. As many of the clinical effects and possible adverse reactions of medazepam appear to be associated with the presence of this major metabolite, the metabolic and pharmacokinetic characteristics of the drug should be considered when using medazepam as an anxiolytic before dentistry or surgery.

Serum medazepam, diazepam, and N-desmethyldiazepam levels after single and multiple oral doses of medazepam.

20 mg of medazepam were taken by mouth by 9 healthy volunteers in an acute absorption study. About a 10-fold variation was found during the first 6 hours after the drug in individual serum medazepam, diazepam, and N-desmethyldiazepam levels. In a subacute study 10 mg of medazepam t.i.d. was given to 10 institutionalized mentally subnormal adults with emotional disorders. After 14 days' treatment serum N-desmethyldiazepam levels were generally above 800 ng/ml, 7 to 8 times higher than the serum medazepam or diazepam levels measured 12 hours after the last dose. No correlation was observed between the serum concentration and efficacy of medazepam.

Actions of iontophoretic phenytoin and medazepam on hippocampal neurons.

In rats anesthetized with methoxyflurane, phenytoin (DPH) and medazepam (MDZ) were administered iontophoretically to pyramidal and granule cells discharging spontaneously or being driven by acetylcholine or glutamic acid. The objectives were to determine if: 1) these anticonvulsant agents exert direct effects on the rates of discharge of hippocampal neurons; 2) similarities exist between responses elicited by DPH and MDZ; and 3) pyramidal and granule cells differ in their responsiveness to the drugs. The firing rates of 38% of spontaneously active neurons were reduced by iontophoretic DPH. The incidence of depression by DPH depended upon the pretest discharge rates of the cells. Only 5% of cells with spontaneous rates less than 12/sec were depressed by DPH, but 80% with rates faster than 12/sec were inhibited. MDZ depressed 79% of spontaneously firing neurons regardless of pretest discharge rate. A majority of neurons whose firing rates were facilitated by either acetylcholine or glutamate were depressed by DPH or MDZ ejected iontophoretically. Pyramidal and granule cells responded similarly to putative transmitters, but differentially to the drugs. MDZ depressed a much greater proportion of spontaneously active granule cells then DPH. Phenytoin and MDZ differed with regard to the incidence of depression of spontaneous discharges, inhibition of slow firing cells, the proportion of granule cells depressed, and the duration of effect. These differences may be due to potency and pharmacokinetic factors or dissimilar mechanisms of action when the compounds are applied directly to single neurons.