Studies on antifungal agents. In vitro activity of novel cis-5-alkoxy (or acyloxy)alkyl-3-phenyl-3-(1H-imidazol-1-ylmethyl)-2-methylisoxazolidine derivatives.

The synthesis and in vitro antifungal activity of a novel series of cis-5-alkoxy(or acyloxy)alkyl-3-phenyl-3-(1H-imidazol-1-ylmethyl)- 2-methylisoxazolidine derivatives (6a-n) are described. The 5-[(4-chlorobenzyloxy)methyl] analogue 6h and the two 5-acyloxymethyl derivatives 6k,l demonstrated the best overall potency. Against Candida stellatoidea, the minimum inhibitory concentrations (MIC's) for 6h,k,l ranged between 0.7 and 2.0 micrograms/ml. The corresponding value for the standard drug ketoconazole was 7-20 micrograms/ml.

Effect of oxamisole on immune parameters of mice infected with murine hepatitis.

The effects of Oxamisole, 2,3,5,6,7,8-hexahydro-2-phenyl-8,8- dimethoxyimidazo[1,2a]pyridine on immune parameters of mice infected with murine hepatitis were investigated. Young Swiss Webster mice were injected intraperitoneally (i.p.) with the Friend-Braunsteiner strain of murine hepatitis virus and with various doses of Oxamisole at 48 h pre- 24 h pre-, and 4 h post-virus exposure. Antiviral activity was seen in the drug-treated mice which was approximated on the basis of 21-day survival frequency and hepatic discoloration, SGOT and SGPT levels and amount of infectious virus recoverable from the liver. On day 4 post-viral exposure, splenic cells from some of the drug- and placebo-treated cells of infected mice injected with Oxamisole, 25 mg/kg/day, produced significantly more interleukin-1 and interleukin-2 than cells of infected mice treated with saline only. Similarly, mice treated with 25 mg/kg/day of this compound had cells with significantly increased antibody-dependent cell-mediated cytotoxicity as compared with placebo treated animals. However, cells from mice treated with Oxamisole did not demonstrate altered natural killer cell activity. It is concluded that Oxamisole, when administered to mice infected with murine hepatitis virus, has antiviral properties which possibly are mediated through the immunomodulatory effects of this compound on the immune system.

Flavodilol: a new antihypertensive agent.

Flavodilol, a new antihypertensive drug, was evaluated in a variety of test systems for better understanding of its biologic properties and the nature of its mechanism of action. Oral administration of the drug to spontaneously hypertensive rats (SHR) lowered arterial blood pressure (ABP) in a dose-related manner, and doses greater than 35 mg/kg increased duration but not magnitude of the response. In contrast, oral administration of flavodilol to normotensive rats did not significantly alter ABP at 35 mg/kg, although larger doses of 75 or 150 mg/kg significantly lowered ABP. In rats with DOCA/salt hypertension, flavodilol effectively lowered ABP to a degree similar to that observed in SHR. At antihypertensive doses, flavodilol did not alter blood pressure responses to a 90 degrees head-up tilt in SHR and did not influence cardiac output in conscious SHR. In addition, flavodilol did not appear to manifest its antihypertensive activity through an interaction with beta-adrenoceptors, dopamine (DA) receptors or prostaglandin synthetase. Daily oral administration of flavodilol to SHR for 4 days resulted in augmented vasopressor responses to exogenously administered epinephrine (EPI) or norepinephrine (NE) and attenuated responses to exogenously administered tyramine. In addition, flavodilol treatment attenuated in a dose-related manner ABP and heart rate (HR) responses of pithed SHR to electrical stimulation of sympathetic nerves. We conclude that flavodilol is an effective antihypertensive drug which decreases the release of NE from postganglionic sympathetic nerves, resulting in attenuation of peripheral noradrenergic function.

Flavodilol: a new antihypertensive agent that preferentially depletes peripheral biogenic amines.

Flavodilol, ((+/-)-7-[2-hydroxy-3-(propylamine)-propoxy]flavone maleate), a new orally effective antihypertensive agent, extensively depleted catecholamines and serotonin in heart tissue of normotensive and spontaneously hypertensive rats (SHR). Dose-response studies demonstrated that greater than or equal to 75% depletion of cardiac norepinephrine (NE) was accompanied by marked blood pressure decline in SHR. In contrast, whole brain biogenic amine levels were decreased only by 15-20% after acute or chronic treatment with antihypertensive doses (35-75 mg/kg). Adrenal epinephrine (EPI) stores were unaffected by acute treatment, although chronic treatment for 18 days with an antihypertensive dose of 75 mg/kg flavodilol decreased EPI by 70%. Acute treatment also decreased serotonin content of spleen by 70-80%. In dogs, a cumulative oral dose of 40 mg/kg decreased catecholamines by greater than or equal to 50% in aorta and heart muscle. Although hypothalamic catecholamine stores appeared to be more susceptible to depletion by flavodilol than catecholamines in other brain regions, these changes did not appear functionally related to blood pressure decreases since analogs of flavodilol without antihypertensive properties produced equivalent or greater depletion of hypothalamic catecholamine stores. In vitro flavodilol promoted spontaneous and potassium-evoked release of dopamine from isolated striatal nerve endings (0.3 microM) and blocked uptake of NE by hypothalamus and hippocampal nerve endings (1 microM), suggesting that biogenic amine depletion in vivo may be caused by an interference with storage and release mechanisms. Despite structural features reminiscent of beta-adrenergic antagonists, flavodilol had low affinity for beta-receptors. Neither was there any inhibition of tyrosine hydroxylase. These findings suggest that the antihypertensive activity of flavodilol results, at least in part, from depletion of sympathetic stores of NE in heart and vascular tissues that moderate adrenergic transmission, thereby decreasing heart rate (HR) and prevailing vascular tone.

Selection of orally active antifungal agents from 3,5-substituted isoxazolidine derivatives based on acute efficacy-safety profiles.

Routine in vitro screening of a new synthetic series of 3,5-substituted 2-methylisoxazolidines revealed that three imidazole analogs (PR 967-248, PR 967-234, and PR 969-566) and, to a lesser extent, a triazole analog (PR 988-399) exerted rather potent antifungal activity against three systemic and four dermatophytic classes of fungi. When tested in vivo for ability to eradicate Candida vaginitis in the rat, the triazole derivative, PR 988-399, was effective after oral administration. In this in vivo test for efficacy, PR 967-234 and PR 969-566 reduced but did not eradicate the infection, while PR 967-248 was inactive. PR 988-399 was, moreover, 4- to 13-fold less potent than the three imidazoles in inhibiting testosterone synthesis in isolated rat Leydig cells. After oral or intravenous administration, PR 988-399 and PR 969-566 elicited the fewest cardiovascular and behavioural side effects in conscious dogs. The rat safety study consisted of oral dosing followed by evaluation of the exploratory motor activity of the naive animals in a novel environment. Motor activity was suppressed least by PR 988-399 and most by PR 969-566. In a battery of mouse behavioural-neuromuscular-drug interaction tests, PR 988-399 and PR 969-566 produced the fewest central-behavioural-neuromuscular signs. These efficacy-safety evaluations were performed with ketoconazole as a positive reference standard. The sequence of drug testing with respect to efficacy-safety considerations appears to be a suitable approach for early detection of orally active antifungal agents such as PR 988-399 for more advanced development.

Drug-induced modifications of the immune response. 12. 4,5-Dihydro-4-oxo-2-(substituted amino)-3-furancarboxylic acids and derivatives as novel antiallergic agents.

The synthesis of a series of novel 4,5-dihydro-4-oxo-2-(substituted amino)-3-furancarboxylic acids, salts, esters, and amides is described. The title compounds when tested in the mediator-induced dermal vascular permeability and active anaphylaxis assays in rats demonstrated moderate to potent antiallergic activity. The [2-trans-(4-methylphenyl)cyclopropyl]amino analogue 53 emerged as the most active derivative. Thus, when administered intraperitoneally to rats at a dose of 100 mg/kg, it inhibited the action of the mediators serotonin, histamine, and bradykinin by 100%. In the active anaphylaxis assay in rats, compound 30 suppressed the edema by 81% at a dose of 100 mg/kg, following intraperitoneal administration.

Studies on antifungal agents. 23. Novel substituted 3,5-diphenyl-3-(1H-imidazol-1-ylmethyl)- 2-alkylisoxazolidine derivatives.

The synthesis and antifungal activity of a novel series of substituted 3,5-diphenyl-3-(1H-imidazol-1-ylmethyl)-2-alkylisoxazolidine derivatives (15-30) are described. The synthesis of the title compounds was accomplished via a 1,3-dipolar cycloaddition reaction of alpha-substituted ketonitrones with appropriate styrene precursors. The compounds when tested in vitro in solid agar cultures exerted a very potent antifungal activity against a wide variety of yeast and systemic mycoses and dermatophytes, especially Trichophyton and Microsporum sp., Epidermophyton floccosum and Candida stellatoidea. The in vitro activity against Aspergillus fumigatus and Candida albicans was moderate to potent. Overall, the two bis(4-chlorophenyl) analogues 18 and 19 were the most potent in vitro compounds, showing MIC values ranging between 0.2 and 7.0 microgram/mL, as compared to 0.2-20.0 micrograms/mL for ketoconazole, which was used as the positive standard in all assays. When tested in vivo in the rat vaginal candidiasis model, derivative 18, although showing significant antifungal activity when compared to controls, was less effective than ketoconazole. The title 3,5-substituted isoxazolidine compounds represent a novel class of potent antifungal agents.

Flavones. 1. Synthesis and antihypertensive activity of (3-phenylflavonoxy)propanolamines without beta-adrenoceptor antagonism.

The synthesis of a series of (3-phenylflavonoxy)propanolamines is described. These compounds were evaluated for potential antihypertensive activity in spontaneously hypertensive rats, as well as for in vivo and in vitro evidence of beta-adrenoceptor antagonism. Some of the compounds of this series exhibited effective antihypertensive properties but did not antagonize beta-adrenergic receptors. These active compounds represent a unique series of effective antihypertensive agents that, despite possessing structural characteristics typical of beta-blockers, does not have beta-adrenergic receptor blocking activity.

PR 879-317A enhances in vitro immune activity of peripheral blood mononuclear cells from patients with Down syndrome.

Down syndrome is associated with immune deficiencies which result in increased incidences of respiratory infections and lymphocytic leukemia. Peripheral blood mononuclear cells (PBMC) from patients with Down Syndrome were assayed in several in vitro assays following incubation in medium or various concentrations of PR 879-317A (2,3,5,6,7,8-hexahydro-2-phenyl-8,8-dimethoxyimidazo (1,2a) pyridine), a selective immunorestorative agent. PBMC of the patients, incubated in medium, exhibited significantly reduced activities in the natural killer (NK) cell, antibody-dependent cell-mediated cytotoxicity (ADCC), T-cell blastogenesis and leukocyte-inhibition factor (LIF) assays. Incubation in PR 879-317A significantly increased the NK and ADCC activities of PBMC from both patients and healthy subjects. However, the effect was much more pronounced on the patients' cells increasing their NK and ADCC activities to normal levels. Incubation in PR 879-317A augmented to normal levels the responses of patients' cells in various assessments of T-cell immunity including blastogenic responses to phytohemagglutinin and concanavalin A and production of LIF. In addition, the number of patients' cells forming spontaneous rosettes with sheep red blood cells was increased following incubation in PR 879-317A. In contrast this compound did not significantly modify the T-cell responses of cells from the healthy subjects suggesting that this compound does not affect normal T-cell function.

The uptake of a substituted acridone by rat mast cells in relationship to histamine release: a possible indicator of exocytosis-induced expansion of the plasma membrane.

A substituted acridone, 10-(2-dimethylaminopropyl)-9-acridone HCl (M-129), was taken up by isolated rat peritoneal and pleural mast cells in direct relationship to the degree of selective histamine release induced by compound 48/80. Other selective releasing agents, i.e., polymyxin B and anti-rat mast cell serum, also augmented uptake of M-129. Augmented uptake of M-129 was inhibited by measures that inhibited selective histamine release, i.e., cold, brief heating of the mast cells, N-ethylmaleimide and ninhydrin. 48/80 did not agument uptake of M-129 in rat erythrocytes or in rat serous fluid cells from which mast cells had been removed. M-129 taken up by mast cells was readily removed by two to three washes. Augmented uptake induced by 48/80 was specific for M-129 and acridone itself. Related compounds, i.e., a quaternary acridone derivative [10-(2-triethylaminoethyl)-9-acridone iodide] (M-231), acridine and acridan did not show augmented uptake. There was no relationship between heptane-water partition coefficients and uptake. It is postulated, based on estimates of cell membrane area, that M-129 is loosely bound to plasma membrane and that the augmented uptake associated with selective histamine release from rat mast cells is due to expanded plasma membrane that results from irreversible or slowly reversible exocytosis.