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The sodium-glucose cotransporter (SGLT) 2 offer a novel approach to treating type 2 diabetes by reducing hyperglycaemia via increased urinary glucose excretion. In the present study, the pharmacokinetic, pharmacodynamic, and pharmacologic properties of all six SGLT2 inhibitors commercially available in Japan were investigated and compared. Based on findings in normal and diabetic mice, the six drugs were classified into two categories, long-acting: ipragliflozin and dapagliflozin, and intermediate-acting: tofogliflozin, canagliflozin, empagliflozin, and luseogliflozin. Long-acting SGLT2 inhibitors exerted an antihyperglycemic effect with lower variability of blood glucose level via a long-lasting increase in urinary glucose excretion. In addition, ipragliflozin and luseogliflozin exhibited superiority over the others with respect to fast onset of pharmacological effect. Duration and onset of the pharmacologic effects seemed to be closely correlated with the pharmacokinetic properties of each SGLT2 inhibitor, particularly with respect to high distribution and long retention in the target organ, the kidney. While all six SGLT2 inhibitors were significantly effective in increasing urinary glucose excretion and reducing hyperglycemia, our findings suggest that variation in the quality of daily blood glucose control associated with duration and onset of pharmacologic effects of each SGLT2 inhibitor might cause slight differences in rates of improvement in type 2 diabetes.

The pharmacological profile of ipragliflozin (ASP1941; (1S)-1,5-anhydro-1-C-{3-[(1-benzothiophen-2-yl)methyl]-4-fluorophenyl}-D: -glucitol compound with L: -proline (1:1)), a novel SGLT2 selective inhibitor, was investigated. In vitro, the potency of ipragliflozin to inhibit SGLT2 and SGLT1 and stability were assessed. In vivo, the pharmacokinetic and pharmacologic profiles of ipragliflozin were investigated in normal mice, streptozotocin-induced type 1 diabetic rats, and KK-A(y) type 2 diabetic mice. Ipragliflozin potently and selectively inhibited human, rat, and mouse SGLT2 at nanomolar ranges and exhibited stability against intestinal glucosidases. Ipragliflozin showed good pharmacokinetic properties following oral dosing, and dose-dependently increased urinary glucose excretion, which lasted for over 12 h in normal mice. Single administration of ipragliflozin resulted in dose-dependent and sustained antihyperglycemic effects in both diabetic models. In addition, once-daily ipragliflozin treatment over 4 weeks improved hyperglycemia with a concomitant increase in urinary glucose excretion in both diabetic models. In contrast, ipragliflozin at pharmacological doses did not affect normoglycemia, as was the case with glibenclamide, and did not influence intestinal glucose absorption and electrolyte balance. These results suggest that ipragliflozin is an orally active SGLT2 selective inhibitor that induces sustained increases in urinary glucose excretion by inhibiting renal glucose reabsorption, with subsequent antihyperglycemic effect and a low risk of hypoglycemia. Ipragliflozin has, therefore, the therapeutic potential to treat hyperglycemia in diabetes by increasing glucose excretion into urine.

These results suggest that SGLT2 selective inhibitor ipragliflozin exerts a beneficial effect on glycaemic control and ameliorates diabetes-associated metabolic abnormalities and complications in STZ-induced diabetic rats, and would be a potential agent for the treatment of type 1 diabetes.

Previously we investigated the pharmacokinetic, pharmacodynamic, and pharmacologic properties of all six sodium-glucose cotransporter (SGLT) 2 inhibitors commercially available in Japan using normal and diabetic mice. We classified the SGLT2 inhibitors with respect to duration of action as either long-acting (ipragliflozin and dapagliflozin) or intermediate-acting (tofogliflozin, canagliflozin, empagliflozin, and luseogliflozin). In the present study, antidiabetic effects of repeated administration of these SGLT2 inhibitors in type 2 diabetic mice were investigated. When repeatedly administered for 4 weeks, all SGLT2 inhibitors significantly exhibited antihyperglycemic, antihyperinsulinemic, and pancreas-protective effects, as well as insulin resistance-improving effects. When compared at doses producing comparable reduction in hyperglycemia across all drugs, the antidiabetic effects of ipragliflozin and dapagliflozin were more potent than those of the other four drugs, but these differences among the six drugs were not statistically significant. Further, an oral glucose tolerance test performed after repeated administration demonstrated significant improvement in glucose tolerance only with ipragliflozin and dapagliflozin, implying improved insulin resistance and secretion. Taken together, these findings demonstrate that, although all SGLT2 inhibitors exert antidiabetic effects in type 2 diabetic mice, these pharmacologic effects might be slightly superior with the long-acting drugs, which are able to provide favorable blood glucose control throughout the day.

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