Todd R. Elworthy

Discovery and optimization of pyridazinone non-nucleoside inhibitors of HIV-1 reverse transcriptase.

A series of benzyl pyridazinones were evaluated as HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs). Several members of this series showed good activity against the wild-type virus and NNRTI-resistant viruses. The binding of inhibitor 5a to HIV-RT was analyzed by surface plasmon resonance spectroscopy. Pharmacokinetic studies of 5a in rat and dog demonstrated that this compound has good oral bioavailability in animal species. The crystal structure of a complex between HIV-RT and inhibitor 4c is also described.

Non-nucleoside inhibitors of HCV polymerase NS5B. Part 2: Synthesis and structure―activity relationships of benzothiazine-substituted quinolinediones

A new series of benzothiazine-substituted quinolinediones were evaluated as inhibitors of HCV polymerase NS5B. SAR studies on this series revealed a methyl sulfonamide group as a high affinity feature. Analogues with this group showed submicromolar potencies in the HCV cell based replicon assay. Pharmacokinetic and toxicology studies were also performed on a selected compound (34) to evaluate in vivo properties of this new class of inhibitors of HCV NS5B polymerase.

Discovery of triazolinone non-nucleoside inhibitors of HIV reverse transcriptase

Novel non-nucleoside inhibitors of HIV-RT that contain pyridazinone isosteres were prepared, and a series of triazolinones were found to be potent inhibitors of HIV replication. These compounds were active against several NNRTI-resistant virus strains. Pharmacokinetic studies indicated that inhibitor 7e has good bioavailability in rats. Several fragments of inhibitor 7c were prepared, and the binding of these compounds to HIV-RT was analyzed by surface plasmon resonance spectroscopy.

Non-nucleoside inhibitors of HCV polymerase NS5B. Part 4: structure-based design, synthesis, and biological evaluation of benzo[d]isothiazole-1,1-dioxides

A series of benzo[d]isothiazole-1,1-dioxides were designed and evaluated as inhibitors of HCV polymerase NS5B. Structure-based design led to the incorporation of a high affinity methyl sulfonamide group. Structure-activity relationship (SAR) studies of this series revealed analogues with submicromolar potencies in the HCV replicon assay and moderate pharmacokinetic properties. SAR studies combined with structure based drug design focused on the sulfonamide region led to a novel and potent cyclic analogue.

Synthesis, pharmacology and pharmacokinetics of 3-(4-Aryl-piperazin-1-ylalkyl)-uracils as uroselective α1A-antagonists

Predominance in the urethra and prostate of the alpha(1A)-adrenoceptor subtype, which is believed to be the receptor mediating noradrenaline induced smooth muscle contraction in these tissues, led to the preparation of alpha(1A)-selective antagonists to be tested as uroselective compounds for the treatment of benign prostatic hyperplasia. Thus, a number of selective alpha(1A)-adrenoceptor antagonists were synthesized and assayed in vitro for potency and selectivity. Dog pharmacokinetic parameters of 12 (RO700004) and its metabolite 40 (RO1104253) were established. The relative selectivity of intravenously administered 12, 40 and standard prazosin to inhibit hypogastric nerve stimulation-induced increases in intraurethral prostatic pressure versus phenylephrine-induced increases in diastolic blood pressure in anesthetized dogs was 76, 71 and 0.6, respectively.

Non-nucleoside inhibitors of HCV polymerase NS5B. Part 3: synthesis and optimization studies of benzothiazine-substituted tetramic acids.

Benzothiazine-substituted tetramic acids were discovered as highly potent non-nucleoside inhibitors of HCV NS5B polymerase. X-ray crystallography studies confirmed the binding mode of these inhibitors with HCV NS5B polymerase. Rational optimization of time dependent inactivation of CYP 3A4 and clearance was accomplished by incorporation of electron-withdrawing groups to the benzothiazine core.

Orally bioavailable prodrugs of a BCS class 2 molecule, an inhibitor of HIV-1 reverse transcriptase

The N-2 position of pyridazinone 1, a potent HIV-1 NNRTI that has limited aqueous solubility, was derivatized into a series of hydroxymethyl esters and carbonates as well as one phosphate. The derivatives served as prodrugs to effectively deliver 1 to rat plasma upon oral treatment at 50 mpk. Increases of 4.3- to 8.6-fold in 24-hour exposure of 1 (over that of parent) were observed while the prodrugs and the hydroxymethyl adduct 2 were undetectable.