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At least 235 records · Page 13Linked to original sources
PubMed1983

Cardiac-slowing amidines containing the 3-thioindone group. Potential antianginal agents.

A series of 3-thioindolamidines (and 3-indolamidines) related to mixidine (1) was studied for cardiac-slowing properties, following the discovery of activity for prototype thioindole 2. Structure-activity relationships were explored, leading to many potent antitachycardiac agents (6-9, 12, 13, 15-17, 20, 23, 24, 30, 34, 35, 45, and 47-49). Relative to 2, cardiac-slowing activity is enhanced by substitution of the indole nitrogen with small (C1-C3) saturated alkyl groups (6-9), unsaturated alkyl groups (12, 13, and 15-17), or a methoxyethyl group (20); replacement of the N-methyl group with alkyl (23) or phenyl groups (24); and extension of the ethylene bridge by two methylene units (34). Dethio (i.e., 3-indole) analogues of 2 with alkyl substitution on the indole nitrogen (47-49) have greater activity as well. Several potent compounds were also found to have minimal myocardial depression (6-9, 13, 45, and 47). Secondary pharmacological testing is reported for thioindoles 2, 6, 7, 9, and 28.

Amidines↗
PubMed2003

Human factor Xa bound amidine inhibitor conformation by double rotational-echo double resonance nuclear magnetic resonance and molecular dynamics simulations.

Double rotational-echo double resonance (double REDOR) NMR was used to investigate the conformation of a (13)C-, (15)N-, and (19)F-labeled inhibitor (Berlex Biosciences compound no. ZK-806299) bound to human factor Xa. Conformationally dependent carbon-fluorine dipolar couplings were measured by (13)C[(19)F] REDOR. Natural abundance carbon signals in the full-echo spectra were removed by (13)C[(15)N] REDOR. Major and minor binding modes were suggested by the NMR data, but only the former had adequate signal to noise for distance determinations. Molecular dynamics simulations restrained by double-REDOR-determined intramolecular (13)C-(19)F distances revealed two models for the dominant binding mode that are consistent with the NMR data. We conclude that ZK-806299 binds similarly to both FXa. Moreover, it appears to bind to FXa in a fashion previously demonstrated for ZK-807834, a more selective FXa inhibitor.

Amidines↗
PubMed1996

Orally active fibrinogen receptor antagonists. 2. Amidoximes as prodrugs of amidines.

The potent and selective GP IIb-IIIa antagonist lamifiban (1, Ro 44-9883) is currently in clinical development as an injectable antithrombotic agent for treating and preventing acute coronary syndromes. However, for secondary prevention of thrombotic occlusions, orally active inhibitors are needed. By means of a prodrug strategy, the modest oral absorption of 1 in mice was improved by a factor of 9. In addition, these studies demonstrated that an amidoxime group can serve as a prodrug functionality for an amidino group. Application of this principle to the structurally related amidino carboxylate 13 led to the amidoxime ester 18 which was absorbed approximately 20 times better, after oral administration to mice, than 13. Due to the modification of the amidino group as well as of the carboxylate group, 18 completely lost its ability to interact with purified platelet GP IIb-IIIa. After oral administration of 18 to rats, dogs, and rhesus monkeys, the bioavailability of the active derivative 13 was 26 +/- 5, 25 +/- 6, and 33 +/- 6%, respectively, and the elimination half-life was 4.1 +/- 1.7, 11.4 +/- 1.1, and 5.1 +/- 1.4 h, respectively. On the basis of these properties, the orally active 18 (Ro 48-3657), a double prodrug of the potent and selective non-peptide GP IIb-IIIa antagonist 13 (Ro 44-3888), was selected as clinical candidate for evaluation as a prophylactic agent in patients at high risk for arterial thrombosis.

Acetates↗
PubMed2001

Phase 2 metabolites of N-hydroxylated amidines (amidoximes): synthesis, in vitro formation by pig hepatocytes, and mutagenicity testing.

A pig hepatocyte culture system was used for phase 2 biotransformation studies in vitro. The viability of the cultured hepatocytes was characterized daily during cultivation by lactate dehydrogenase release into the supernatant and albumin synthesis of the cells. The metabolic activity of the hepatocyte cultures was measured by 7-ethoxycoumarin (ECOD) and 7-ethoxyresorufin O-deethylation (EROD). The viability and metabolic activity of these pig hepatocytes were preserved for several days by culturing the cells in a monolayer culture system. Besides the known reduction of N-hydroxylated benzamidine (benzamidoxime) (2) to benzamidine (1), glucuronidation and, to a much smaller extent, sulfation of 2 to benzamidoxime O-glucuronide (3) and benzamidoxime O-sulfate (4) by cultured pig hepatocytes were found. The analyses were performed using HPLC and LC/MS studies. For unequivocal assignment, the hitherto unknown metabolites 3 and 4 were synthesized and characterized by spectroscopic techniques. Examination of benzamidoxime O-glucuronide and benzamidoxime O-sulfate for mutagenicity by means of the Ames test revealed that both phase 2 conjugates have no mutagenic effects in the TA98 and TA100 strains. So the phase 2 conjugation of benzamidoxime is significant in terms of detoxification.

Amidines↗
PubMed2000

Biophysical and structural properties of DNA.diC(14)-amidine complexes. Influence of the DNA/lipid ratio.

Cationic liposomes are used as vectors for gene delivery both in vitro and in vivo. Comprehension of both DNA/liposome interactions on a molecular level and a description of structural modifications involved, are prerequisites to an optimization of the transfection protocol and, thus, successful application in therapy. Formation and stability of a DNA/cationic liposome complex were investigated here at different DNA:lipid molar ratios (rho). Isothermal titration calorimetry (ITC) of cationic liposomes with plasmid DNA was used to characterize the DNA-lipid interaction. Two processes were shown to be involved in the complex formation. A fast exothermic process was attributed to the electrostatic binding of DNA to the liposome surface. A subsequent slower endothermic reaction is likely to be caused by the fusion of the two components and their rearrangement into a new structure. Fluorescence and differential scanning calorimetry confirmed this interpretation. A kinetic model analyzes the ITC profile in terms of DNA/cationic liposome interactions.

Amidines↗
PubMed1991

Inhibition of Cryptosporidium parvum in neonatal Hsd:(ICR)BR Swiss miceby polyether ionophores and aromatic amidines.

Cryptosporidicidal effects of two polyether ionophores (maduramicin and alborixin), a fluorinated 4-quinolone (enrofloxacin), and three analogs of pentamidine were evaluated in a suckling mouse bioassay. Treatment with all compounds except enrofloxacin and one of the pentamidine analogs [1,3-di(4-imidazolinophenoxy)propane] resulted in significant (P less than 0.05) reductions in oocyst excretion.

4-Quinolones↗