New 5-aminoacyl-5,10-dihydro-11H-dibenzo[b,e][1,4]diazepin-11-ones with antiarrhythmic activity.

A series of new 5-substituted tricyclic 5,10-dihydro-11H-dibenzo[b,e][1,4]-diazepin-11-ones was identified as potential antiarrhythmic agents against bradyarrhythmias [1, 2]. The in vitro and in vivo interactions of the compounds with muscarinic receptors and the antiarrhythmic activity were examined. In receptor binding studies some derivatives showed a high affinity to the cardiac M2 receptor (Ki 10 nmol/l), an equal or smaller affinity to cortical M1 receptor and a lower affinity to the glandular M3 binding site. Functional experiments showed the derivatives as competitive antagonists with high affinity to the cardiac and smaller affinity to the intestinal muscarinic receptor. In vivo experiments correspond with the M2 selectivity. First the vagal or agonist-induced bradycardia was inhibited in rats and guinea pigs while the McNA-343 induced increase of blood pressure, methacholine-induced bronchi and bladder constriction as well as the salivation were inhibited only at higher doses. In conscious cats the tachycardia was examined in comparison with pupillomotoricity. The effect duration and the therapeutical range were determined in comparison to the M2 selective blocking agent AF-DX116. The antiarrhythmic activity was examined compared to quinidine sulfate in CaCl2-arrhythmia of rats, in atrial fibrillation and atrial flutter in dogs according to Scherf [2] and in electric induced atrial fibrillation under vagal stimulation in cats. In the atrial arrhythmias the derivatives are clearly longer effective than quinidine sulfate. The antiischemic activity was examined in the two-stages coronary ligature in dogs according to Harris. The long-running regularization of ectopies (about 2 h after i.v. injection) occurred without decrease of the heart rate, an effect particularly convenient to therapy of bradycardic dysrhythmias.

[Antifibrillatory and anti-arrhythmic action of 3-carbethoxyamino-5-dimethylamino-acetyl iminodibenzyl hydrochloride (Bonnecor, AWD 19-166, GS 015) on models of myocardial ischemia]. / Antifibrillatorische und antiarrhythmische Wirksamkeit von 3-Carbethoxyamino-5-dimethylamino-acetyl-iminodibenzyl-hydrochlorid (Bonnecor, AWD 19-166, GS 015) an Modellen der Myocardischämie.

The intense antifibrillatory and antiarrhythmic actions of GS 015, a derivative of the novel structure series of the 5-(beta-aminoacyl)-3-carbalkoxyamino-iminodibenzyles, are demonstrated on models of myocardial ischaemia: antifibrillatory action on the acute coronary occlusion in the conscious rat (1.0 mg/kg i.v.) and antiarrhythmic action on the two-step coronary ligature in the conscious dog according to Harris (2.0 mg/kg i.v. and 5.0 mg/kg orally). On the strength of the present results it is discussed that GS 015 is first of all suitable for influencing "early arrhythmias" with re-entry mechanism and only in the second line for taking an influence on "late arrhythmias" which arise from the occurrence of ectopic focuses. The substance seems suitable for preventing terminal arrhythmias in patients with ischaemic heart disease as well as for treating arrhythmias in the acute stage of myocardial infarction.

[Circulatory action and adverse effects of 3-carbethoxyamino-5-dimethylamino-acetyl-iminodibenzyl hydrochloride (Bonnecor, AWD 19-166, GS 015) in the dog and cat]. / Kreislaufwirkungen und Nebenwirkungen von 3-Carbethoxyamino-5-dimethylamino-acetyl-iminodibenzyl-hydrochlorid (Bonnecor, AWD 19-166, GS 015) an Hund und Katze.

The haemodynamic and cardiac effects of GS 015, a substance of the series of the novel 5-(dialkyl-aminoacyl)-3-carbalkoxyamino-10,11-dihydro-5H-dibenz-[b ,f]-azepines with very potent antifibrillatory and antiarrhythmic actions, are studied on anaesthetized dogs and cats by means of the catheter technique. The clinical symptoms and the therapeutic range were tested on conscious animals. On the strength of the present results it can be stated that GS 015, given at pharmacodynamically effective doses, does not cause any circulatory side effects. A negative inotropic effect appears only at increased doses. Like other antiarrhythmic drugs, GS 015 possesses a limited therapeutic range which should be taken into consideration particularly in case of cardiac insufficiency. But an application seems possible also in patients during the acute stage of myocardial infarction.

[Pharmacokinetics and pharmacodynamics of 3-carbethoxyamino-5-dimethylamino-acetyl-iminodibenzyl hydrochloride (Bonnecor, AWD 19-166, GS 015) in the dog]. / Pharmakokinetik und Pharmakodynamik von 3-Carbethoxyamino-5-dimethylamino-acetyl-iminodibenzyl-hydrochlorid (Bonnecor, AWD 19-166, GS 015) am Hund.

The antiarrhythmic action of GS 015 was studied in proportion to its plasma concentrations ascertained in parallel, making use of the model of the two-step coronary ligature in the conscious dog. Blood levels of 1.0 microgram/ml (2 mg/kg i.v.) or of 0.8 microgram/ml (5 mg/kg orally) brought about a complete suppression of ectopic arrhythmias. The limit concentration for this effect is about 0.5 microgram/ml.

[Antiarrhythmic effectiveness of 3-carbalkoxyamino-5-(omega-aminoacyl)-10,11-dihydro-5H-dibenz-[b,f]- azepines]. / Antiarrhythmische Wirksamkeit von 3-Carbalkoxyamino-5-(omega-aminoacyl)-10,11-dihydro-5H-dibenz-[b,f]- azepinen.

The derivatives of a novel structure series of dibenzazepines dispose of intense antiarrhythmic properties. The relations between structure and effect in comparison with the antiarrhythmically active derivatives of phenothiazine (Ethmozine) are discussed. When substituting the beta-aminopropionyl chain with cyclic residue by means of a dimethylaminoacyl chain there appears a marked antifibrillatory action besides of the intense antiarrhythmic one. The compound 17, the 3-carbethoxyamino-5-dimethylaminoacetyl-dibenzazepine, proved to be the most efficacious compound in the course of the basic screening on two models: action on the effective refractory period in the rabbit's atrium and aconitin-induced arrhythmia in the conscious rat. In comparison with Ethmozin, an antiarrhythmic agent of the phenothiazine type, 17 shows a somewhat lower efficacy in case of i.v. application, but a distinctly intenser one was stated after oral administration. A profound test on the models: two-step coronary ligature in the dog according to Harris and electrofibrillation in the cat's heart, revealed an equally intense antiarrhythmic action but a considerably intenser antifibrillatory one. Therefore the compound 17 (abbreviated designation in the USSR: GS 015 or in the GDR: AWD 19-166) was provided for a thorough pharmacological and toxcological study.