New basic esters of 2-phenyl-3-methyl-4-oxo-4H-1-benzopyran-8-carboxylic acid endowed with spasmolytic properties. Synthesis and pharmacological-pharmacokinetic evaluation.

In order to obtain new analogs of flavoxate endowed with higher stability and possibly higher potency, a new series of basic esters of 2-phenyl-3-methyl-4-oxo-4H-1-benzopyran-8-carboxylic acid (MFCA) has been prepared and investigated. Derivatives in which the structure of flavoxate was modified by branching and lengthening of the estereal alkyl chain were synthesized, together with the conformationally restricted N-piperidinyl derivatives. Esters containing in their structure various alicyclic tertiary amines which are present in natural or synthetic drugs endowed with spasmolytic properties, mainly of anticholinergic nature, were also prepared. The stability in aqueous solution, acute toxicity in mouse, and in vitro spasmolytic properties of the new compounds were investigated in comparison with flavoxate. Based on the results obtained from this screening procedure, 3 compounds were selected for further investigation. In this phase, further pharmacological and stability testing as well as preliminary animal pharmacokinetic investigations were carried out. The obtained results suggested the choice of 1,1-dimethyl-2-(1-piperidinyl)ethyl 2-phenyl-3-methyl-4-oxo-4H-1-benzopyran-8-carboxylate HCl (Rec 151 2053, terflavoxate, CAS 86433-39-8) as a candidate for preclinical development. The deeper pharmacological characterization of this compound, carried out mainly in comparison with flavoxate, terodiline, and oxybutynin confirmed its good spasmolytic activity.

Cardiovascular activities of the new potent and long-lasting antihypertensive calcium entry blocker (+-)-3-ethyl,5-methyl,2- ([2-(formylamino)-ethyl]- thiomethyl)-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicar box ylate.

BBR 2160 ((+-)3-ethyl,5-methyl,2-([2-(formylamino)-ethyl]- thiomethyl)-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarb oxy late, CAS 118587-22-7) is a new calcium entry blocker (CEB) which completely displaces 3H-nitrendipine from binding sites, is 10 times more potent than amlodipine (A) and equiactive with nifedipine (N). On the rat aorta contracted by 10 mmol/l Ca++, or 45 mmol/l K+, BBR 2160 shows higher CEB activity than N and A, achieving the maximum effect on voltage operated channels-induced contractions in 6 h, while N takes about 2 h. BBR 2160, N and A negatively affect the chronotropism on spontaneously beating, and inotropism on electrically driven guinea pig atria, respectively. In vitro BBR 2160 has marked vasoselectivity. Administered orally to conscious hypertensive rats (SHR) and renal hypertensive dogs (RHD), it caused a dose-dependent reduction in systolic blood pressure with a relatively slow onset, peak effect at 3-6 h and duration over 6 h. BBR 2160 and A have more pronounced activity on SHR than on normotensive rats (NR) (ED20 NR/SHR 3.3 for both compounds), while the antihypertensive and hypotensive activities of N are in the same dose-range (ED20 NR/SHR 1.3). No tolerance develops to the antihypertensive effects of BBR 2160 after five days' dosing up to 3.2 mg/kg in SHR and 1 mg/kg in RHD. In instrumented conscious normotensive dogs BBR 2160, N and A mostly lower diastolic blood pressure and total peripheral resistance, and do not increase total oxygen consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis and biological evaluation of substituted benzo[h]cinnolinones and 3H-benzo[6,7]cyclohepta[1,2-c]pyridazinones: higher homologues of the antihypertensive and antithrombotic 5H-indeno[1,2-c]pyridazinones.

Several substituted benzo[h]cinnolinones 3 and 3H-benzo[6,7]cyclohepta[1,2-c]pyridazinones 4, which were designed as less rigid congeners of 5H-indeno[1,2-c]pyridazinones 2, were synthesized and tested as antihypertensive, inotropic, antithrombotic, antiinflammatory, and antiulcer agents. While the seven-membered ring derivatives displayed only antithrombotic properties, which were comparable to that of acetylsalicylic acid, most of the benzo[h]cinnolinones exhibited significant antihypertensive, inotropic, and antithrombotic properties. In this respect, the 8-amino (3b) and 8-acetylamino (3c) together with the 4,4a-dehydro analogue of 3c (11) were found to possess the most potent and long-lasting antihypertensive activity. In particular, the dextro isomer of 3c was more active than the racemic form, with lower tachycardiac effects. Unlike the lower homologues 2, none of the compounds showed significant antiinflammatory or antiulcer activity.

Pharmacological activities of the main metabolite of flavoxate 3-methylflavone-8-carboxylic acid.

The pharmacological properties of 3-methylflavone-8-carboxylic acid (MFCA), the main metabolite of flavoxate, have been studied in vitro and in vivo. MFCA did not display antispasmodic activity on isolated organs contractions induced by histamine, acetylcholine or CaCl2, nor did it exhibit significant affinity for the rat brain alpha- and beta-adrenergic, serotoninic, muscarinic, D2, opiate and Ca2+ receptors. However, it showed a remarkable phosphodiesterase (PDE) inhibiting activity. Moreover in vivo studies indicate an interesting activity of MFCA which inhibited the rat urinary bladder voiding contractions, increased bladder volume capacity and decreased micturition pressure in the rat cystometric recordings. The activity of MFCA in the two in vivo experimental models, probably related to cAMP-PDE inhibitory properties, suggests that flavoxate's therapeutical potential might be partially sustained by its main metabolite.

1-(2-pyridinyl)piperazine derivatives with antianaphylactic, antibronchospastic, and mast cell stabilizing activities.

New 1-(2-pyridinyl)piperazine derivatives were synthesized and tested as inhibitors of the reaginic passive cutaneous anaphylaxis in the rat (PCA), of the histamine-induced bronchospasm in the guinea pig, and of the rat mesenteric mast cell degranulation induced by compound 48/80. On the basis of test results, a series of N-(substituted phenyl)-omega-[4-(2-pyridinyl)-1-piperazinyl]alkanamides was prepared. The nature of substituents at the anilide ring strongly influenced mast cell stabilizing activity, whereas it was less determining in the case of the other two tests. No clear correlation between the most common physicochemical parameters (pi, sigma, Vw volume) of substituents and activity could be detected. With regard to the position of substituents at the anilide ring, the rank order of potency, in the PCA and bronchoconstriction tests, was para greater than meta greater than ortho. Introduction of substituents in the 1-(2-pyridinyl)piperazinyl moiety of the N-(substituted phenyl)propanamide derivatives hardly affected activity, or the effect was deleterious. Some of the new compounds exhibited a simultaneous remarkable activity in all the three assays employed.

Mechanism of flavoxate antispasmodic activity comparative in vitro studies.

In order to clarify the pharmacological activity of flavoxate, its effect on the tone and spontaneous activity of the guinea-pig isolated ureter and of the muscle strip from rat urinary bladder were studied. Flavoxate, as well as papaverine, reduced all three parameters considered on the guinea-pig isolated ureter, namely: peristaltic motility, endoluminal pressure and longitudinal muscle contractility. In the same test, verapamil (a calcium antagonist), emepronium and atropine (both anticholinergic drugs) were used for comparison. Using strips of rat urinary bladder depolarized by KCl, flavoxate, papaverine and verapamil displayed a relaxant activity, while anticholinergic compounds such as atropine, hyoscine and emepronium failed to relax this tissue. In another series of experiments the effects of flavoxate and anticholinergic drugs on the contraction elicited by vagal electrical stimulation of the guinea-pig isolated stomach in toto were assayed. The results obtained suggest that the action of flavoxate is due to direct smooth muscle relaxation and does not involve anticholinergic activity.

[New 2,4-dibromo-6-(N-cyclohexyl-N-methyl)-aminomethylanilides of derivatives of cysteine and cystine with expectorant activity]. / Nuove 2,4-dibromo-6-(N-cicloesil-N-metil)aminometilanilidi di derivati della cisteina e della cistina ad attività espettorante.

New 2,4-dibromo-6-(N-cyclohexyl-N-methyl)aminomethylanilides of N-acetylcysteine and N-acetyl-S-carboxymethylcisteine derivatives, N-benzyloxycarbonylcysteine and N,N'-bisbenzyloxycarbonylcystine were synthesized. The compounds were tested for the expectorant activity in rabbit and mouse. N,N'-Bisbenzyloxycarbonylcystin-bis [2,4-dibromo-6-(N-cyclohexyl-N-methyl)aminomethyl]anilide (XIX) was selected for further investigations.

Pharmacological studies on the mode of action of flavoxate.

Previous studies on the mode of action of flavoxate have shown that the drug exerts a selective and direct muscle relaxant activity. In order to study the mode of action of flavoxate, the following activities were investigated: calcium blocking, inhibition of cyclic AMP phosphodiesterase (PDE), local anaesthetic activity, the effects on the synthesis and release of prostaglandins. In the K+-depolarized guinea-pig taenia coli, contracted by CaCl2, flavoxate and papaverine showed a moderate calcium antagonistic activity. Anticholinergic drugs, such as atropine and emepronium, did not exert a similar action. The antispasmodic activity of a drug can be correlated with inhibition of cyclic AMP phosphodiesterase, and since papaverine is a potent PDE inhibitor, we tested flavoxate for this activity. Flavoxate exerted a PDE inhibitory activity about three and five times greater than that of aminophylline in tissues homogenates of guinea-pig ureter and urinary bladder, respectively. It also showed the same local anaesthetic activity of lidocaine. Finally, the synthesis and release of prostaglandins by urinary bladder muscle in vitro have been investigated before and after treatment with flavoxate. Myolytic activity of papaverine and flavoxate do not involve inhibition of prostaglandins synthesis in rat urinary bladder in vitro. Therefore, the mode of action of flavoxate can be related to a superimposition of myotropic, calcium antagonistic and local anaesthetic activity.

Denzimol, a new anticonvulsant drug. II. General pharmacological activities.

The paper reports on the pharmacological properties of N-[beta-[4-(beta-phenylethyl)phenyl]-beta-hydroxyethyl]imidazole hydrochloride (denzimol, Rec 15-1533), a compound endowed with anticonvulsant properties, and its possible side effects. Effects on the CNS, effects on vigilance and general motility are similar to those of phenytoin and occur at doses much above anticonvulsant levels. The drug has good in vitro antihistamine, anticholinergic and anti-5-HT activity which accounts for the effects on the gastrointestinal system e.g. inhibition of gastric secretion and motility and anti-ulcer properties. There was no significant effect on the cardiovascular system or respiration, except an interesting antiarrhythmic activity.

Toxicological and pharmacological properties of fenticonazole, a new topical antimycotic.

The acute oral and subchronic (6 weeks) topical toxicity of alpha-(2,4-dichlorophenyl)-beta,N-imidazolylethyl 4-phenylthiobenzyl ether nitrate (fenticonazole, Rec 15/1476) was studied in mice, rats, guinea pigs and beagle dogs. The acute oral LD50 in mice and rats was found to be 3000 mg/kg, while the i.p. acute toxicity was 1191 mg/kg in mice and between 309 and 440 mg/kg in rats. The acute oral LD50 in beagle dogs was 1000 mg/kg. Percutaneous subchronic (6 weeks) toxicity was evaluated in guinea pigs and beagle dogs. Both species of animals exhibited no toxic effect attributable to the treatment with fenticonazole and no histopathologic changes were attributed to the drug treatment. Fenticonazole did not affect numerous pharmacological and physiological parameters (blood pressure, heart rate, pulmonary ventilation, nor did it interfere with the activity of histamine, adrenaline, noradrenaline and acetylcholine). It does not possess analgesic or antiinflammatory activity at high doses (100 mg/kg p.o.). In mice it exhibits a slight CNS depressant activity, milder than that of miconazole.

Irritation and toxicity studies with fenticonazole applied topically to the skin and mucous membranes.

Various tests were used in order to ascertain any irritating, sensitising or toxic potential of alpha-(2,4-dichlorophenyl)-beta,N-imidazolylethyl 4-phenylthiobenzyl ether nitrate (fenticonazole, Rec 15/1476) when applied to the skin or to mucous membranes in gel or cream formulation. When instilled into the conjunctival sac in rabbits fenticonazole led to a slight reddening of the mucosa in only one animal. The reddening appeared 1 h after treatment and disappeared within 24 h. Guinea pigs topically treated for 20 days with fenticonazole 2% gel or cream showed mild erythema which appeared 5 days after the beginning of the treatment and virtually disappeared at the end of the treatment. The treatment with fenticonazole 2% gel or cream did not induce sensitisation. Fenticonazole was not phototoxic or photosensitising when a 2% gel or cream formulation was applied topically to guinea pigs, at the dosage of 0.1 ml per animal.