Derivatives of a novel scaffold, C-phenyl 1-thio-D-glucitol, were prepared and evaluated for sodium-dependent glucose cotransporter (SGLT) 2 and SGLT1 inhibition activities. Optimization of substituents on the aromatic rings afforded five compounds with potent and selective SGLT2 inhibition activities. The compounds were evaluated for in vitro human metabolic stability, human serum protein binding (SPB), and Caco-2 permeability. Of them, (1S)-1,5-anhydro-1-[5-(4-ethoxybenzyl)-2-methoxy-4-methylphenyl]-1-thio-D-glucitol (3p) exhibited potent SGLT2 inhibition activity (IC(50) = 2.26 nM), with 1650-fold selectivity over SGLT1. Compound 3p showed good metabolic stability toward cryo-preserved human hepatic clearance, lower SPB, and moderate Caco-2 permeability. Since 3p should have acceptable human pharmacokinetics (PK) properties, it could be a clinical candidate for treating type 2 diabetes. We observed that compound 3p exhibits a blood glucose lowering effect, excellent urinary glucose excretion properties, and promising PK profiles in animals. Phase II clinical trials of 3p (TS-071) are currently ongoing.

The mechanism of the elevation of intracellular glutathione induced by low-dose g g-rays was examined in RAW 264.7 cells. The expression of mRNA for g g-glutamylcysteine synthetase (g g-GCS) increased soon after g g-ray (0.5 Gy) irradiation, and peaked between 3 h and 6 h post-irradiation. A dose of 0.25 to 0.5 Gy was optimum for induction of g g-GCS mRNA expression at 3 h post-irradiation. The effect of inhibitors of activator protein-1 (AP-1) and nuclear factor k kB (NF-k kB) on the radiation-induced g g-GCS gene expression was then examined. The induction of g g-GCS mRNA expression was significantly suppressed when AP-1 DNA binding, but not NF-k kB DNA binding, was inhibited. Finally, electrophoretic mobility shift assay showed that the low-dose radiation markedly increased the DNA binding of AP-1, but not NF-k kB, soon after irradiation. These results suggest that the increase of glutathione levels in RAW 264.7 cells by low-dose g g-ray irradiation is mediated by transcriptional regulation of the g g-GCS gene, predominantly through the AP-1 binding site in its promoter.

These results suggest that GlyT1 inhibitors including TASP0315003 may be useful for the treatment of cognitive dysfunction and the negative symptoms of schizophrenia without having undesirable central nervous system side effects.

ABSTRACT:MGS0039 (3-(3,4-dichlorobenzyloxy)-2-amino-6-fluorobicyclo-[3.1.0]hexane-2,6-dicarboxylic acid) has been identified as a potent and selective antagonist for metabotropic glutamate receptors. However, the oral bioavailability of MGS0039 is 10.9% in rats, due to low absorption. Several prodrugs, synthesized to improve absorption, exhibited 40 to 70% bioavailability in rats. This study investigated in vitro metabolism using liver S9 fractions from both cynomolgus monkeys and humans and oral bioavailability in cynomolgus monkeys to select the prodrug most likely to exhibit optimal pharmacokinetic profiles in humans. In monkeys, transformation to active substance was observed (5.9-72.8%) in liver S9 fractions, and n-butyl, n-pentyl, 3-methylbutyl, and 4-methylpentyl ester prodrugs exhibited high transformation ratios (>64%). C max levels and F values after oral dosing increased to 4.1-to 6.3-fold and 2.4-to 6.3-fold, respectively, and a close relationship between transformation ratios and C max and F values was observed, indicating that the hydrolysis rate in liver S9 fractions is the key factor in determining oral bioavailability in monkeys. In humans, n-hexyl, n-heptyl, n-octyl, 5-methylbutyl, and 6-methylpentyl ester prodrugs exhibited high transformation ratios (>65%) in liver S9 fractions. With these prodrugs, n-hexyl, n-heptyl, and 5-methylpentyl ester, almost complete recovery (96-99%) was obtained. Given the transformation ratio, we anticipated that the n-heptyl alkyl ester prodrug would exhibit the highest oral bioavailability of active substances in humans, if the hydrolysis rate in liver S9 fractions is indeed the key factor in determining oral bioavailability in humans. On this basis, MGS0210 (3-(3,4-dichlorobenzyloxy)-2-amino-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid n-heptyl ester) seems to be a promising candidate among MGS0039 prodrugs.

Background: TP0463518 is a novel hypoxia-inducible factor prolyl hydroxylase inhibitor developed to aid in the treatment of anemia associated with chronic kidney disease (CKD) and is expected to increase erythropoietin (EPO) derived from liver. Two phase I studies were conducted in healthy volunteers (HV) and CKD patients undergoing hemodialysis (i.e., HD patients) or those not undergoing dialysis (i.e., ND patients). Methods: Pharmacokinetics, pharmacodynamics, and safety profiles of TP0463518 were assessed. Forty HV received single oral doses of TP0463518 at 3, 6, 11, 20, and 36 mg or placebo. Twenty ND patients received single doses of TP0463518 at 1, 6, and 11 mg and 9 HD patients received TP0463518 at 1 and 11 mg doses. To identify the source organ of EPO, glycosylation patterns were determined using percentage migrated isoform (PMI) values. Results: Declining renal function slowed elimination of TP0463518 and increased the mean AUC_0–∞. ∆E_max of serum EPO in 11-mg groups of HV, ND patients, and HD patients were 24.37 ± 11.37, 201.57 ± 130.34, and 1,324.76 ± 1,189.24 mIU/mL respectively. A strong correlation was ­observed between logarithm conversions of ∆E_max and AUC_0–∞ with correlation coefficients of 0.945. PMI values of blood after TP0463518 administration were elevated to similar or higher levels in comparison with those of umbilical cord blood, which mainly contains liver-derived EPO. Conclusions: TP0463518 induced dose-dependent EPO production, mainly derived from the liver in HV and CKD patients. These results suggest that TP0463518 is a new strategy for treating anemia in CKD, which can be used regardless of renal functions.