Structure-based lead optimization to improve antiviral potency and ADMET properties of phenyl-1H-pyrrole-carboxamide entry inhibitors targeted to HIV-1 gp120.

We are continuing our concerted effort to optimize our first lead entry antagonist, NBD-11021, which targets the Phe43 cavity of the HIV-1 envelope glycoprotein gp120, to improve antiviral potency and ADMET properties. In this report, we present a structure-based approach that helped us to generate working hypotheses to modify further a recently reported advanced lead entry antagonist, NBD-14107, which showed significant improvement in antiviral potency when tested in a single-cycle assay against a large panel of Env-pseudotyped viruses. We report here the synthesis of twenty-nine new compounds and evaluation of their antiviral activity in a single-cycle and multi-cycle assay to derive a comprehensive structure-activity relationship (SAR).

In vitro metabolism and stability of the actinide chelating agent 3,4,3-LI(1,2-HOPO).

The hydroxypyridinonate ligand 3,4,3-LI(1,2-HOPO) is currently under development for radionuclide chelation therapy. The preclinical characterization of this highly promising ligand comprised the evaluation of its in vitro properties, including microsomal, plasma, and gastrointestinal fluid stability, cytochrome P450 inhibition, plasma protein binding, and intestinal absorption using the Caco-2 cell line. When mixed with active human liver microsomes, no loss of parent compound was observed after 60 min, indicating compound stability in the presence of liver microsomal P450.

A systematic screen of FDA-approved drugs for inhibitors of biological threat agents.

Background: The rapid development of effective medical countermeasures against potential biological threat agents is vital. Repurposing existing drugs that may have unanticipated activities as potential countermeasures is one way to meet this important goal, since currently approved drugs already have well-established safety and pharmacokinetic profiles in patients, as well as manufacturing and distribution networks. Therefore, approved drugs could rapidly be made available for a new indication in an emergency.

The stereoselective sulfate conjugation of 4'-methoxyfenoterol stereoisomers by sulfotransferase enzymes.

The presystemic sulfate conjugation of the stereoisomers of 4'-methoxyfenoterol, (R,R')-MF, (S,S')-MF, (R,S')-MF, and (S,R')-MF, was investigated using commercially available human intestinal S9 fractions, a mixture of sulfotransferase (SULT) enzymes. The results indicate that the sulfation was stereospecific and that an S-configuration at the β-OH carbon of the MF molecule enhanced the maximal formation rates with (S,R')-MF  (S,S')-MF  (R,S')-MF ≈ (R,R')-MF, and competition studies demonstrated that (S,R')-MF is an effective inhibitor of (R,R')-MF sulfation (IC(50) = 60 μM). In addition, the results from a cDNA-expressed human SULT isoform screen indicated that SULT1A1, SULT1A3, and SULT1E1 can mediate the sulfation of all four MF stereoisomers.

Lead optimization of antimalarial propafenone analogues.

Previously reported studies identified analogues of propafenone that had potent antimalarial activity, reduced cardiac ion channel activity, and properties that suggested the potential for clinical development for malaria. Careful examination of the bioavailability, pharmacokinetics, toxicology, and efficacy of this series of compounds using rodent models revealed orally bioavailable compounds that are nontoxic and suppress parasitemia in vivo. Although these compounds possess potential for further preclinical development, they also carry some significant challenges.

Discovery and optimization of benzotriazine di-N-oxides targeting replicating and nonreplicating Mycobacterium tuberculosis.

Compounds bactericidal against both replicating and nonreplicating Mtb may shorten the length of TB treatment regimens by eliminating infections more rapidly. Screening of a panel of antimicrobial and anticancer drug classes that are bioreduced into cytotoxic species revealed that 1,2,4-benzotriazine di-N-oxides (BTOs) are potently bactericidal against replicating and nonreplicating Mtb. Medicinal chemistry optimization, guided by semiempirical molecular orbital calculations, identified a new lead compound (20q) from this series with an MIC of 0.

Development of a new generation of 4-aminoquinoline antimalarial compounds using predictive pharmacokinetic and toxicology models.

Among the known antimalarial drugs, chloroquine (CQ) and other 4-aminoquinolines have shown high potency and good bioavailability. Yet complications associated with drug resistance necessitate the discovery of effective new antimalarial agents. ADMET prediction studies were employed to evaluate a library of new molecules based on the 4-aminoquinolone-related structure of CQ.

Effect of resveratrol on 17beta-estradiol sulfation by human hepatic and jejunal S9 and recombinant sulfotransferase 1E1.

The purpose of this study was to investigate the sulfation of resveratrol (3,5,4'-trihydroxystilbene) and its potential to exhibit drug-drug interactions via sulfation. The possible interaction of resveratrol with 17beta-estradiol (E2), a major estrogen hormone and prototypic substrate for sulfate conjugation, was studied. Resveratrol and E2 are both known to undergo sulfate conjugation catalyzed by human sulfotransferases (SULTs).

Endoscopic placement of the small-bowel video capsule by using a capsule endoscope delivery device.

Background: Capsule endoscopy performed via the traditional peroral route is technically challenging in patients with dysphagia, gastroparesis, and/or abnormal upper-GI (UGI) anatomy.

Objective: To describe the indications and outcomes of cases in which the AdvanCE capsule endoscope delivery device, which has recently been cleared by the Food and Drug Administration, was used.

Design: Retrospective, descriptive, case series.

Glucuronidation of trans-resveratrol by human liver and intestinal microsomes and UGT isoforms.

Resveratrol (trans-resveratrol, trans-3,5,4'-trihydroxystilbene) is a naturally occurring stilbene analogue found in high concentrations in red wine. There is considerable research interest to determine the therapeutic potential of resveratrol, as it has been shown to have tumour inhibitory and antioxidant properties. This study was performed to investigate the glucuronidation of resveratrol and possible drug interactions via glucuronidation.

Glucuronidation of 1'-hydroxyestragole (1'-HE) by human UDP-glucuronosyltransferases UGT2B7 and UGT1A9.

Estragole (4-allyl-1-methoxybenzene) is a naturally occurring food flavoring agent found in basil, fennel, bay leaves, and other spices. Estragole and its metabolite, 1'-hydroxyestragole (1'-HE), are hepatocarcinogens in rodent models. Recent studies from our laboratory have shown that glucuronidation of 1'-HE is a major detoxification pathway for estragole and 1'-HE, accounting for as much as 30% of urinary metabolites of estragole in rodents.