Abstract 16947: Sotagliflozin, a Dual SGLT 1 and 2 Inhibitor, Has High Membrane Affinity and Hydrocarbon Core Location Compared With Empagliflozin

Abstract

Background: The dual SGLT-1 and 2 inhibitor sotagliflozin (sota) reduced atherothrombotic events and hospitalization for worsening heart failure in patients with diabetes in clinical trials (SCORED, SOLOIST). Unlike selective SGLT2 inhibitors such as empagliflozin (empa), sota binds with higher affinity to SGLT1, which is located in the intestine, kidney, heart, brain, and vascular endothelial cells. To elucidate the physico-chemical basis for differences in tissue distribution and receptor affinity, we compared the effects of these drugs on membrane binding and molecular location. Methods: Membranes reconstituted from cardiac phospholipid and cholesterol were used to measure drug partitioning across a range of cholesterol concentrations. Multilamellar vesicles were prepared as mixtures of cardiac phospholipid (CPL), cholesterol, and each agent at 30 μM or vehicle. Drug-membrane partitioning was determined by rapid centrifugation and UV/Vis spectrophotometry. In parallel experiments, we used small angle x-ray scattering (SAXS) to identify drug location in model membranes containing phosphatidylcholine and cholesterol. Results: Sota had a membrane partition coefficient (8590 ± 2078) that was 16-fold higher than empa (519 ± 195, p<0.001) in CPL membranes. This high membrane affinity was preserved over a range of cholesterol levels compared to empa (p<0.001). Consistent with high membrane affinity, SAXS analysis showed that sota had a location evidenced by a broad increase in electron density in the hydrocarbon core extending to approximately 20 Å from the membrane center. By contrast, empa had a location limited to the polar headgroup region, consistent with its lower lipophilicity and tissue penetration. Conclusions: Sota had high membrane affinity and distinct location in the hydrocarbon core compared to empa. This may contribute to the effect of its dual SGLT-1 and 2 inhibition in vivo across various tissues including the heart. These distinct membrane interactions may also partially explain the reduced atherothrombotic risk as demonstrated in outcome trials with sota but not selective SGLT-2 inhibitors.