Phenotypic screening reveals a highly selective phthalimide-based compound with antileishmanial activity

Pharmacophores such as hydroxyethylamine (HEA) and phthalimide (PHT) have been identified as potential synthons for the development of compounds against various parasitic infections. In order to further advance our progress, we conducted an experiment utilising a collection of PHT and HEA derivatives through phenotypic screening against a diverse set of protist parasites. This approach led to the identification of a number of compounds that exhibited significant effects on the survival of Entamoeba histolytica, Trypanosoma brucei, and multiple life-cycle stages of Leishmania spp. The Leishmania hits were pursued due to the pressing necessity to expand our repertoire of reliable, cost-effective, and efficient medications for the treatment of leishmaniases. Antileishmanials must possess the essential capability to efficiently penetrate the host cells and their compartments in the disease context, to effectively eliminate the intracellular parasite. Hence, we performed a study to assess the effectiveness of eradicating L. infantum intracellular amastigotes in a model of macrophage infection. Among eleven L. infantum growth inhibitors with low-micromolar potency, PHT-39, which carries a trifluoromethyl substitution, demonstrated the highest efficacy in the intramacrophage assay, with an EC50 of 1.2 +/- 3.2 μM. Cytotoxicity testing of PHT-39 in HepG2 cells indicated a promising selectivity of over 90-fold. A chemogenomic profiling approach was conducted using an orthology-based method to elucidate the mode of action of PHT-39. This genome-wide RNA interference library of T. brucei identified sensitivity determinants for PHT-39, which included a P-type ATPase that is crucial for the uptake of miltefosine and amphotericin, strongly indicating a shared route for cellular entry. Notwithstanding the favourable properties and demonstrated efficacy in the Plasmodium berghei infection model, PHT-39 was unable to eradicate L. major infection in a murine infection model of cutaneous leishmaniasis. Currently, PHT-39 is undergoing derivatization to optimize its pharmacological characteristics.

Compassionate Use of Tecovirimat for the Treatment of Monkeypox Infection

This case series describes the clinical resolution of systemic symptoms and lesions, along with any adverse events, in patients with monkeypox infection who were treated with tecovirimat on a compassionate use basis.

Phase 2 Trial of Iberdomide in Systemic Lupus Erythematosus

BACKGROUND

Iberdomide, a cereblon modulator promoting degradation of the transcription factors Ikaros and Aiolos, which affect leukocyte development and autoimmunity, is being evaluated for the treatment of systemic lupus erythematosus (SLE).

METHODS

In this phase 2 trial, we randomly assigned patients in a 2:2:1:2 ratio to receive oral iberdomide (at a dose of 0.45, 0.30, or 0.15 mg) or placebo once daily for 24 weeks, in addition to standard medications. The primary end point at week 24 was a response on the SLE Responder Index (SRI-4), which was defined as a reduction of at least 4 points in the Systemic Lupus Erythematosus Disease Activity Index 2000 score (a 24-item weighted score of lupus activity that ranges from 0 to 105, with higher scores indicating greater disease activity), no new disease activity as measured on the British Isles Lupus Assessment Group 2004 index, and no increase of 0.3 points or more in the Physician's Global Assessment score (on a visual-analogue scale ranging from 0 [no disease activity] to 3 [maximal disease]).

RESULTS

A total of 288 patients received the assigned intervention: 81 received iberdomide at a dose of 0.45 mg, 82 received iberdomide at a dose of 0.30 mg, 42 received iberdomide at a dose of 0.15 mg, and 83 received placebo. At week 24, the percentages of patients with an SRI-4 response were 54% in the iberdomide 0.45-mg group, 40% in the iberdomide 0.30-mg group, 48% in the iberdomide 0.15-mg group, and 35% in the placebo group (adjusted difference between the iberdomide 0.45-mg group and the placebo group, 19.4 percentage points; 95% confidence interval, 4.1 to 33.4; P = 0.01), with no significant differences between the groups that received the lower doses of iberdomide and the group that received placebo. Iberdomide-associated adverse events included urinary tract and upper respiratory tract infections and neutropenia.

CONCLUSIONS

In this 24-week, phase 2 trial involving patients with SLE, iberdomide at a dose of 0.45 mg resulted in a higher percentage of patients with an SRI-4 response than did placebo. Data from larger, longer trials are needed to determine the efficacy and safety of iberdomide in SLE. (Funded by Bristol Myers Squibb; ClinicalTrials.gov number, NCT03161483; EudraCT number, 2016-004574-17.).

Discovery of ARD-2585 as an Exceptionally Potent and Orally Active PROTAC Degrader of Androgen Receptor for the Treatment of Advanced Prostate Cancer

We report herein the discovery of exceptionally potent and orally bioavailable PROTAC AR degraders with ARD-2585 being the most promising compound. ARD-2585 achieves DC50 values of ≤0.1 nM in the VCaP cell line with AR gene amplification and in the LNCaP cell line carrying an AR mutation. It potently inhibits cell growth with IC50 values of 1.5 and 16.2 nM in the VCaP and LNCaP cell lines, respectively, and achieves excellent pharmacokinetics and 51% of oral bioavailability in mice. It is more efficacious than enzalutamide in inhibition of VCaP tumor growth and does not cause any sign of toxicity in mice. ARD-2585 is a promising AR degrader for extensive investigations for the treatment of advanced prostate cancer.

Schistosomicidal and prophylactic activities of phthalimido-thiazoles derivatives on schistosomula and adult worms

Schistosomiasis is a major public health problem worldwide, especially in poor communities. Praziquantel is currently the only drug available to treat schistosomiasis and it shows low efficacy against schistosomula and juveniles stages of Schistosoma mansoni, allowing lower cure rate in areas with high endemicity. There is an urgent need to identify new antischistosomal drugs. Previous works identified phthalimido-thiazoles as privileged structures acting as schistossomicidal agent. In this way, a phthalimido-thiosemicarbazide intermediate and eight phthalimido-thiazoles derivatives were evaluated concerning the in vitro antischistosomal activity compounds in adult phase of Schistosoma mansoni and examined alterations on the tegumental surface. The results revealed that compounds 2f, 2 l and 2 m caused significant mortality in adult worms at concentrations range of 20 μg/mL to 100 μg/mL. These compounds were also selected in view to verify the activity against the schistosomula. Compound 2 m promoted 100% of mortality of larval forms until doses of 2.5 μg/mL within 48 h. In addition, when compound 2 m was administered orally at dose of 200 mg/kg for 5 consecutive days to the infected mouse with adult schistosomes, a reduction in the parasite burden was observed. Furthermore, scanning electron microscopy revealed that compound 2 m kill the parasite by tegumental damage and bubbles generation.

Peculiarities of Participation of DNA Methyltransferases in the Mechanisms of Storage, Impairment, and Recovery of Conditioned Food Aversion Memory

We studied the participation of DNA-methylation processes in the mechanisms of memory storage and reconsolidation, amnesia induction, and in recovery of the conditioned food aversion memory in edible snails. It was found that daily injections of DNA methyltransferases inhibitor over 3 days combined with a reminder of a conditioned food stimulus did not affect memory storage. The administration of DNA methyltransferase inhibitors did not suppress induction of amnesia caused the NMDA receptor antagonist/reminder. Injections of DNA methyltransferase inhibitors combined with the reminder led to memory recovery in 3 days after amnesia induction. Thus, DNA methyltransferase inhibitors in the same doses did not affect storage and reconsolidation of memory, as well as the mechanisms of amnesia induction. At the same time, injections of inhibitors led to memory recovery, apparently, due to disruption of reactivation and amnesia development.

Activities of 2-phthalimidethyl nitrate and 2-phthalimidethanol in the models of nociceptive response and edema induced by formaldehyde in mice and preliminary investigation of the underlying mechanisms

The activities of 2-phthalimidethyl nitrate (PTD-NO) and 2-phthalimidethanol (PTD-OH) were recently demonstrated in models of pain and inflammation. We expanded our investigation by evaluating their activities in models of nociceptive and inflammatory pain and inflammatory edema, the preliminary pharmacokinetic parameter for PTD-NO and the role of opioid and cannabinoid pathways in the activity of analogs. Per os (p.o.) administration of PTD-NO or PTD-OH, 1h before intraplantar injection of formaldehyde, inhibited both phases of the nociceptive response (500 and 750 mg/kg) and paw edema (125, 250, 500 and 750 mg/kg). After p.o. administration of PTD-NO, peak plasma concentrations of PTD-NO and PTD-OH were found 0.92 and 1.13 h, respectively. The plasma concentrations of PTD-NO were higher than those of PTD-OH. Intraperitoneal (i.p.) administration of CB1 (AM251) or CB2 (AM630) cannabinoid receptor antagonists (4 or 8 mg/kg, -30 min) or opioid antagonist naltrexone (5 or 10mg/kg, -30 min) did not affect the antinociceptive activities of the analogs. AM251 (8 mg/kg, i.p., -30 min) attenuated the antiedematogenic activity of both analogs, while naltrexone (10mg/kg, i.p., -30 min) only attenuated the antiedematogenic activity of PTD-NO. The antiedematogenic activities of both analogs were not affected by the CB2 cannabinoid antagonist AM630 (4 or 8 mg/kg, i.p., -30 min). Concluding, we expanded the knowledge on the activities of PTD-NO and PTD-OH by showing that these phthalimide analogs also exhibit marked activity in models of nociceptive and inflammatory pain and inflammatory edema. Opioid and cannabinoid mechanisms partially mediate the anti-inflammatory, but not the antinociceptive activity.

Newer N-Phthaloyl GABA Derivatives with Antiallodynic and Antihyperalgesic Activities in Both Sciatic Nerve and Spinal Nerve Ligation Models of Neuropathic Pain

BACKGROUND

There is considerable research evidence supporting a palliative role for gamma-aminobutyric acid (GABA)-ergic neurotransmission and voltage-gated sodium channel blockade in neuropathic pain conditions. Hence, the present study was undertaken to assess the peripheral analgesic, antiallodynic and antihyperalgesic activities of the synthesized structural analogues of GABA.

METHODS

The screening study included acute tissue injury, chronic constriction injury (CCI), and spinal nerve ligation (SNL) models of neuropathic pain.

RESULTS

All of the tested compounds sup-pressed the acetic acid-induced writhing response significantly in comparison to the control. In particular, compound JVP-8 was observed to be the most active compound with percent inhibition greater than that of the standard drug aspirin (97.8% inhibition of writhing response as against 97.0% shown by aspirin). In neuropathic pain studies, compound JVP-5 (100 mg/kg i.p.) emerged as the most active compound affording maximum protection against dynamic allodynia and mechanical hyperalgesia in the CCI model, and against spontaneous pain and mechanical hyperalgesia in SNL rats.

CONCLUSION

In this study, we have demonstrated that combining phthalimide pharmacophore with GABA has evolved compounds effective for the treatment of neuropathic pain.

DNA methylation in breast and colorectal cancers

DNA methylation is one of several epigenetic changes observed in cells. Aberrant methylation of tumor suppressor genes, proto-oncogenes, and vital cell cycle genes has led many scientists to investigate the underlying cellular mechanisms of DNA methylation under normal and pathological conditions. Although DNA methylation is necessary for normal mammalian embryogenesis, both hypo- and hypermethylation of DNA are frequently observed in carcinogenesis and other pathological disorders. DNA hypermethylation silences the transcription of many tumor suppressor genes, resulting in immortalization of tumor cells. The reverse process, demethylation and restoration of normal functional expression of genes, is augmented by DNA methylation inhibitors. Recent studies suggest that DNA hypomethylation may also control gene expression and chromosomal stability. However, the roles of and relationship between hypomethylation and hypermethylation are not well understood. This review provides a brief overview of the mechanism of DNA methylation, its relationship to extrinsic stimulation including dietary intake and aging, and of abnormally methylated DNA in breast and colorectal cancers, which could be used as prognostic and diagnostic markers.

[Selective I(f) channel inhibition: an alternative for treating coronary artery disease?]

Several clinical studies demonstrate the importance of the heart rate for the cardiovascular morbidity and mortality. Over the last 50 years, some thought has been given to those substances that selectively reduce the heart rate. It is now recognized that I(f) ion channels of the sinus node play a major role in the automatism and modulation of the heart rate. Substances that selectively reduce the heart rate should decrease myocardial oxygen consumption and increase oxygen delivery via the prolonged diastolic coronary perfusion. Direct inotropic effects, however, are unlikely. In principle, anti-anginal and anti-ischemic effects of specific bradycardic substances can be expected. The clinical experience with some of the former bradycardic substances has not been sufficiently convincing. The more recent ivabradine (Procoralan presents an exception to this, as it successfully completed a clinical program for the treatment of chronically stable angina pectoris. In this review article, specific bradycardic substances (= I(f) channel inhibitors) are presented together with the corresponding experimental and clinical studies. The studies were selected against the background of the efficacy of I(f) channel inhibitors in the therapy of cardiovascular disease. As only ivabradine has completed a study on 5,000 patients, the discussion on that particular I(f) channel inhibitor is somewhat extensive. In addition, prospective possibilities and limitations of bradycardic substances are presented.

Sinus tachyarrhythmias and the specific bradycardic agents: a marriage made in heaven?

A relatively novel group of drugs that inhibit the funny current in the sinus node pacemaker cells, the so-called specific bradycardic agents, are likely to play a significant role in the management of a wide range of cardiovascular disorders, including the sinus tachyarrhythmias. This comprehensive review initially provides an insight into these agents, their historical background, and their mechanism of action. It then discusses the differential diagnosis of the sinus tachyarrhythmias (normal sinus tachycardia, inappropriate sinus tachycardia, postural orthostatic tachycardia syndrome, and sinus node reentry tachycardia), elaborates on their pathophysiologic basis, and provides up-to-date evidence-based information on their optimum management. The specific bradycardic agents, by the very nature of their mode of action, may prove ideal therapies for the management of the sinus tachyarrhythmias, and this is explored at every stage.

Design, synthesis, and structure-activity relationships of phthalimide-phenylpiperazines: a novel series of potent and selective alpha(1)(a)-adrenergic receptor antagonists

Beginning from the screening hit and literature alpha(1)-adrenergic compounds, a hybridized basic skeleton A was proposed as the pharmacophore for potent and selective alpha(1a)-AR antagonists. Introduction of a hydroxy group to increase the flexibility afforded B which served as the screening model and resulted in the identification of the second-generation lead 1. Using the Topliss approach, a number of potent and selective alpha(1a)-AR antagonists were discovered. In all cases, binding affinity and selectivity at the alpha(1a)-AR of S-hydroxy enantiomers were higher than those of the R-hydroxy enantiomers. As compared to the des-hydroxy analogues, the S-hydroxy enantiomers had slightly lower binding affinity at alpha(1a)-AR but gained more than 2-fold selectivity for alpha(1a)-AR over alpha(1b)-AR, and 2- to 6-fold selectivity for alpha(1a)-AR over alpha(1d)-AR. They also had less cross activities against a panel of 25-35 peripheral and CNS receptors. The S-hydroxy enantiomers 23 and 24 (K(i) = 0.29 nM, 0.33 nM; alpha(1b)/alpha(1a) >5690, >6060; alpha(1d)/alpha(1a) = 186, 158, respectively) were slightly less potent but much more selective at alpha(1a)-AR than tamsulosin (K(i) = 0.13 nM, alpha(1b)/alpha(1a) = 14.8, alpha(1d)/alpha(1a) = 1.4). In the functional assay, the S-hydroxy enantiomers 20, 23, and 24 were less potent than tamsulosin in inhibiting contractions of rat prostate tissue but more selective in the inhibition of tissue contractions of rat prostate versus rat aorta. Compound 24 was selected as the development candidate for the treatment of BPH.

In vivo treatment of mutant FLT3-transformed murine leukemia with a tyrosine kinase inhibitor

Somatic mutation of the FLT3 gene, in which the juxtamembrane domain has an internal tandem duplication, is found in 20% of human acute myeloid leukemias and causes constitutive tyrosine phosphorylation of the products. In this study, we observed that the transfection of mutant FLT3 gene into an IL3-dependent murine cell line, 32D, abrogated the IL3-dependency. Subcutaneous injection of the transformed 32D cells caused leukemia in addition to subcutaneous tumors in C3H/HeJ mice. To develop a FLT3-targeted therapy, we examined tyrosine kinase inhibitors for in vitro growth suppression of the transformed 32D cells. A tyrosine kinase inhibitor, herbimycin A, remarkably inhibited the growth of the transformed 32D cells at 0.1 microM, at which concentration it was ineffective in parental 32D cells. Herbimycin A suppressed the constitutive tyrosine phosphorylation of the mutant FLT3 but not the phosphorylation of the ligand-stimulated wild-type FLT3. In mice transplanted with the transformed 32D cells, the administration of herbimycin A prolonged the latency of disease or completely prevented leukemia, depending on the number of cells inoculated and schedule of drug administration. These results suggest that mutant FLT3 is a promising target for tyrosine kinase inhibitors in the treatment of leukemia.

Induction of apoptosis and inhibition of cellular proliferation as a dual approach to treatment of ovarian cancer

Inhibition of mitosis or induction of apoptosis are pathways at which anti tumour therapies could be aimed. This study evaluates the actions of CGP52411 (cell growth inhibitor) and transforming growth factor beta1 (TGFbeta1) (inducer of apoptosis) alone and in combination on two ovarian carcinoma cell lines (PEO1 and OVCAR3). In both cell lines TGFbeta1 treatment increased the level of apoptotic cells and CGP52411 treatment reduced EGF stimulated cell growth. Combined treatment further reduced cell numbers in PEO1 cultures, demonstrating that dual therapy aimed at both aspects of cell regulation has a greater anti tumour action.

Therapy of human transitional cell carcinoma of the bladder by oral administration of the epidermal growth factor receptor protein tyrosine kinase inhibitor 4,5-dianilinophthalimide

Epidermal growth factor receptor (EGF-R), a transmembrane glycoprotein that mediates the mitogenic response of cells to epidermal growth factor, is highly expressed on malignant human bladder cancer cells. The 4,5-dianilinophthalimides represent a novel class of inhibitors of the EGF-R family of tyrosine kinase with selectivity at the enzymatic and cellular levels. Two compounds of this class, CGP 54211 and CGP 53353, inhibited tyrosine kinase activity of the EGF-R in five different human transitional cell carcinoma lines. The compounds also produced cytostasis in vitro. Highly metastatic human 253J B-V cells were implanted in the bladder wall of nude mice. The daily oral administration of CGP 54211 inhibited the level of EGF-R phosphorylation in this tumor; necrosis and inhibition of tumor growth paralleled this inhibition.

4,5-bis(4-fluoroanilino)phthalimide: A selective inhibitor of the epidermal growth factor receptor signal transduction pathway with potent in vivo antitumor activity

Deregulated signal transduction via the epidermal growth factor (EGF) receptor family of tyrosine protein kinase growth factor receptors is associated with proliferative diseases such as cancer and psoriasis. In an attempt to selectively block signal transduction from the EGF receptor, we have synthesized a new class of dianilino-phthalimide tyrosine protein kinase inhibitors with selectivity for the EGF receptor tyrosine protein kinase. 4, 5-Dianilino-phthalimide (DAPH 1) was metabolized in vitro by mouse liver fractions and in vivo. The major metabolite has been identified as 4-(4-hydroxyanilino)-5-anilino-phthalimide. To specifically block this biotransformation (hydroxylation), we have synthesized 4,5-bis(4-fluoroanilino)phthalimide (DAPH 2), a potent and selective EGF receptor tyrosine protein kinase inhibitor. DAPH 2 inhibits the EGF receptor and protein kinase C beta2 enzymes with equal potency. In cells, DAPH 2 inhibits signal output from the EGF receptor, but not from other classes of receptor protein tyrosine kinases, such as the platelet-derived growth factor receptor, fibroblast growth factor receptor, insulin-like growth factor I receptor, and insulin receptor. Selective antitumor activity was demonstrated in vivo at well-tolerated doses in mice. This publication describes the biological profile of DAPH 2 and investigates its cellular and in vivo mechanism of action.

Effects of prenylamine and AQ-A 39 on reentrant ventricular arrhythmias induced during the late myocardial infarction period in conscious dogs

The effects of prenylamine (PNL) and AQ-A 39 on sustained ventricular tachycardia (SVT) were studied by programmed stimulation in conscious dogs 4-10 days after ligation of the left anterior descending (LAD) coronary artery. In 8 of 16 dogs developing SVT in the control, PNL (3 mg/kg intravenously, i.v.) suppressed inducibility of SVT and slowed the rate of tachycardia in 6 other animals. In a separate group of 10 dogs with inducible SVT, AQ-A 39 (4 mg/kg i.v.) abolished elicitation of tachycardia in 3 dogs and decreased its rate in 6 other dogs. Neither drug affected normal conduction significantly, but PNL impaired slow conduction in the infarct zone, as indicated by prolongation of late potential. Both agents increased the effective refractory period (ERP) of infarcted and normal ventricular myocardium and prolonged the corrected QT interval. PNL and AQ-A 39 exert notable efficacy in preventing infarcted heart from severe ventricular arrhythmias. Prolongation of ventricular refractoriness and repolarization, as well as decreased slow conduction in ischemically damaged myocardium, are major mechanisms accounting for the effectiveness of these drugs against ventricular arrhythmias.

Terephthalamidine: past and future

Terephthalamidine (NSC 57155) is one of 800 terephthalanilides and related compounds which were synthesized and tested preclinically in the late 1950's and early 1960's. Based upon their activity against murine leukemias, some of these agents were tested briefly in clinical trials at that time. Despite the observation of responses, the compounds were dropped because of severe and unusual neurotoxicity. More recently, terephthalamidine has been screened for antitumor activity and chosen for further clinical investigation by the NCI's Project for the Review of Old Drugs (P.R.O.D.) because of its novel structure and spectrum of preclinical activity. The current availability of a plasma assay for the drug permits further study of its clinical pharmacokinetics and pharmacodynamics and, perhaps, the development of improved scheduling strategies.

[The intraoperative use of falipamil (AQ-A39), a new calcium antagonist with specific bradytropic properties]

Tachycardia caused by surgical stimulation can compromise the myocardial oxygen balance and may also lead to a reduction of cardiac output. Conventional drugs with negative chronotropic effects also cause reduction of inotropy. Recent so-called specific bradytropic agents are expected to act merely upon chronotropy without affecting pressure of the systemic or coronary circulation. The goal of this study was to investigate the effects of a calcium channel blocker. Falipamil, on the circulation controlling excessive intraoperative tachycardia. PATIENTS AND METHODS. In this study 15 patients, aged 32 to 73 years, mean 55 +/- 12 were investigated. The cardiac risk classes included classification I-III, according to Goldman. The patients underwent major abdominal or thoracoabdominal operations. Monitoring consisted of a radial arterial cannula, as well as a 7 French Swan-Ganz catheter, which was introduced via the internal jugular vein. Determination of cardiac output was done using the thermodilution technique with a Kimray Medical Association Oklahoma City model 3500; related indexes were calculated. Electrophysiological data were read from the ECG. The recorded QT interval was corrected for heart rate according to the formula of Hegglin and Holzmann. Anesthesia consisted of premedication with diazepam, 0.1 mg/kg, 1 h preoperatively. Anesthesia was induced with thiopentone, 5 mg/kg, and fentanyl, 1.5 micrograms/kg. After giving 1 mg alcuronium, succinylcholine, 1 mg/kg, was used for intubation. Anesthesia was continued using ventilation with O2: N2O 1:2 and intermittent doses of fentanyl and alcuronium. When tachycardia occurred at a rate higher than 100 beats per minute, a dose of 2 micrograms/kg fentanyl was administered to deepen the anesthesia. If this had no influence, control readings were taken and subsequently falipamil 2 mg/kg was injected. After that the hemodynamic parameters were monitored for 1, 2, 3, 5, 10, and 20 min. Statistical analysis was performed using the analyses of variance, followed by the Newman-Keuls test. The level of significance was p less than 0.05. RESULTS. The means and standard deviations of the hemodynamic parameters following induction of anesthesia (0) and at the peak rate are shown in Table 1. The mean increase in heart rate at that time was 38 +/- 18% and the QT and RR interval were reduced concomitantly. Both times the QT measured and the QT corrected for rate did not significantly differ from each other. (ABSTRACT TRUNCATED AT 400 WORDS)

A controlled study with taltrimide and sodium valproate: valproate effective in partial epilepsy

Taltrimide was compared with valproate and placebo in 17 patients with intractable epilepsy being on carbamazepine monotherapy. Taltrimide (400 mg/day), valproate (1000 mg/day) or placebo were added to the treatment for periods of 3 months using a randomized cross-over design. Serum carbamazepine concentrations remained within the therapeutic range throughout the trial. Thirteen patients completed the study. In partial epilepsy of 7 the seizure frequency was reduced by 27% during valproate (p less than 0.05), compared with placebo, while no improvement was found during taltrimide. In 6 with primary generalized epilepsy, the number of seizures was reduced by 49% during taltrimide and by 38% during valproate, but neither effect was significant, compared with placebo. Headache was reported by 3 patients while on taltrimide. One with hypersensitivity history developed petecchiae and nasal bleeding during taltrimide and, therefore, the treatment was stopped. The three other interruptions were independent of taltrimide. Thus, the only statistically significant effect in this study was that of valproate in partial epilepsy.

Substituted cyclic imides as potential anti-gout agents

N-substituted cyclic imides of phthalimide, 2,3-dihydrohalazine-1,4-dione, and diphenimide were shown to reduce the serum uric acid levels in normal and hyperuric mice at 20 mg/kg/day I.P. for 14 days. The agents were potent inhibitors of commercial xanthine dehydrogenase and xanthine oxidase enzyme activities with IC50 values from 10(-7) to 10(-8) M concentrations of drug.

Effects of bradycardic agents on ischaemic myocardium and perfusion in anesthetized dogs

The effects of several new specific bradycardic agents, AQ-A39 and AQ-AH 208, were evaluated in two models of myocardial ischaemia in anesthetized dogs. In the first model, equal bradycardic doses of AQ-AH 208 and propranolol were compared for their effects on coronary collateral blood flow in dogs subjected to an acute coronary artery occlusion. AQ-AH 208 produced a significant (P less than 0.05) increase (35%) in transmural collateral perfusion whereas propranolol had no effect. Atrial pacing to control heart rate only partially negated the beneficial effect of AQ-AH 208 on collateral flow. In the second model of ischaemia, AQ-AH 208 and AQ-A39 were evaluated for their effects on subendocardial segment shortening (% SS) and regional myocardial blood flow in dogs subjected to 15 minutes of coronary artery occlusion, followed by 3 hours of reperfusion. Both compounds produced similar decreases in heart rate (24%) and increases in the endocardial/epicardial distribution of collateral blood flow. During occlusion and throughout reperfusion, AQ-AH 208 and AQ-A39 resulted in a significant improvement in % SS in the ischaemic-reperfused region. These results suggest that specific bradycardic agents may have potential for therapeutic use in certain types of myocardial ischaemia by several different mechanisms.

Comparison of AQ-A 39 with propanolol and placebo in ischaemic heart disease

In a randomized, controlled study 10 male patients with angiographically confirmed ischaemic heart disease received AQ-A 39 (falipamil), a heart rate reducing agent in a single intravenous dose (2 mg kg-1) in comparison to propranolol (0.1 mg kg-1). Both drugs reduced heart rate in supine position slightly. The rise of heart rate induced by orthostasis was diminished by AQ-A 39 to 4 +/- 2 beats min-1 and by propranolol 9 +/- 2 beats min-1. After submaximal exercise heart rate during placebo was 129 +/- 3, during AQ-A 39 113 +/- 3 and during propranolol 103 +/- beats min-1. Systolic arterial pressure decreased by propranolol only. The double product obtained by placebo was 231 +/- 10 while it was for 194 +/- 9 after AQ-A 39 and 158 +/- 6 mmHg min-1 after propranolol, respectively. Both substances increased exercise time as compared to placebo. Furthermore, AQ-A 39 increased noradrenaline plasma levels in the upright position and after submaximal exercise compared to the values obtained following placebo. The dose of isoproterenol necessary to induce an increase of heart rate by 20 beats min-1 was after AQ-A 39 4.2 times greater and following propranolol 9.2 times greater than during placebo. The results suggest that AQ-A 39 will be useful in the short term management of patients with ischaemic heart disease.

[Therapy of perioperative sinus tachycardia with the new calcium antagonist falipamil]

The haemodynamic responses after application of 100-200 mg falipamil (5,6-dimethoxy-2-(3-((alpha (3,4-dimethoxy)-phenylethyl) methylamino)propyl)phthalimidine, AQ-A 39) a new calcium channel blocker with specific action on the sinus node, was studied in 11 patients with perioperative sinus tachycardia (greater than 120/min). A drop in the heart rate of at least 10% could be observed in all patients. In 8 patients 100 mg falipamil decreased the mean heart rate from 130 +/- 19 to 97 +/- 8/min 5 min after the application (p less than 0.001). In the resting 3 patients a second dose of falipamil was injected because of insufficient clinical response. In these patients the mean heart rate dropped from 162 +/- 27 to 125 +/- 40/min 10 min after the second dose. No significant changes of the blood pressure could be observed. Falipamil may become a valuable drug for the therapy of sinus tachycardia due to catecholamines during the perioperative period.

Biochemical and clinical studies on epileptic patients during two phase I trials with the novel anticonvulsant taltrimide

Taltrimide (2-phthalimidoethanesulphon-N-isopropylamide), a lipophilic derivative of taurine and a potent anticonvulsant in animal studies, was administered in daily doses of 1 and 2 g for 2 weeks with an interval of 2.5 months in 2 phase I clinical trials to 9 drug-resistant epileptic patients. Seizures and EEG were recorded, and routine laboratory studies conducted. Concentrations of antiepileptic drugs in plasma, of amino acids in urine and plasma, and contents of amino acids, homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and cyclic nucleotides in the cerebrospinal fluid were determined. Although no clinical or neurophysiological effects were observed, an increase in the cerebrospinal fluid contents of HVA and cyclic nucleotides and changes in the concentrations of antiepileptic drugs and amino acids were found. The concentrations of HVA correlated with those of 5-HIAA and also with those of the main active metabolite of taltrimide. Biochemical changes due to taltrimide treatment resembled only partly those found after taurine treatment.

[Electrophysiologic and hemodynamic effects of the new bradycardia-inducing substance AQ-A 39]

AQ-A 39 is a new agent with specific bradycardic action on the sinus node. In this study the electrophysiologic and hemodynamic effects of this compound were investigated in 24 patients with various cardiac diseases. The results show: AQ-A 39 causes a significant decrease in enhanced sinus rate. The bradycardic action is more profound at higher sinus rates. In sinus rhythm of normal frequency or, in sinus bradycardia, sinus rate remains unchanged or increases even in the case of sick sinus node syndrome. Conductivity of the AV-node is significantly improved. QT- and QTc-interval increase dose dependently. Other cardiac conduction times and refractory intervals are not significantly changed. In exercise-induced myocardial ischemia increased left ventricular filling pressures are diminished. The extent of this decrease parallels the reduction in heart rate. AQ-A 39 appears to be suitable to reduce inadaequate increases in sinus rate, and seems to be of particular interest in surgical cases or intensive care emergencies as well as in acute ischemic heart disease.

Hypolipidemic activity of phthalimide derivatives. 7. Structure-activity studies of indazolone analogues

The apparent benefit of limiting serum cholesterol and triglyceride levels either by dietary restriction or drug therapy has prompted work in our laboratories toward development of a suitable antihyperlipidemic agent. We have demonstrated the antihyperlipidemic activity of a series of phthalimide derivatives in rodents to be significantly greater than that of clofibrate at a dose of 20 mg/(kg day), intraperitoneally. Here we report the synthesis and biological evaluation of a series of indazolone derivatives, which are heterocycles that are structurally related to the phthalimides . In general, structure-activity relationships within the phthalimide series may be extended to the indazolones . While indazolone itself is only moderately active, N1-carbethoxy substitution produced a more active compound. Substitution of the N2 position with an n-butyl group afforded the most active compound, as also seen in the phthalimide series. Aromatic substitution with electron-releasing and -withdrawing groups lessened the antihyperlipidemic activity.

Effect of nifedipine and AQ-A 39 on the sinoatrial and atrioventricular nodes of the rabbit and their antiarrhythmic action on atrioventricular nodal reentrant tachycardia

The effects of two drugs that apparently block slow inward current--nifedipine and the new compound AQ-A 39--were studied on the isolated sinoatrial (SA) and atrioventricular (AV) nodes of the rabbit heart using intracellular microelectrodes. Nifedipine and AQ-A 39 both slowed the sinus rate associated with a decrease in the rate of diastolic depolarisation. Conduction through the AV node was consistently impaired; this effect was enhanced with increasing atrial rates or with decreasing coupling intervals of premature beats. The action potential amplitude was significantly reduced in SA nodal and upper (AN) AV nodal fibres but was not significantly affected in lower (NH) AV nodal and in atrial fibres. The maximum diastolic potential showed little or no alteration. In all fibre types studied, the action potential duration was shortened with nifedipine but was significantly prolonged with AQ-A 39. Prevention of AV nodal reentrant tachycardia by nifedipine was related to an increase in the effective refractory period of the AV node. AQ-A 39 prevented the tachycardia by both slowing of AV nodal conduction and by prolongation of action potential duration in the AV nodal and atrial compartments of the reentrant circuit associated with the appearance of different gap phenomena of the AV conduction. The maximum possible A-H interval was, however, not shortened by either drug and single atrial echo beats could still be initiated. The results suggest that nifedipine and AQ-A 39 both have a direct depressant action on the slow inward current-dependent electrical activity of the SA and AV node but have opposite effects on the repolarisation phase resulting in different antiarrhythmic mechanisms.

Possible antineoplastic agents I

A few thalidomide and glutarimide derivatives were synthesized. Several compounds possessed significant antineoplastic activity against Ehrlich ascites carcinoma in Swiss albino mice.