TABLE 3
Mass-spectral characterization of primary metabolites of saxagliptin identified in human plasma samples after administration of a single oral dose of [14C]saxagliptin to healthy volunteers
 |  | ||
|---|---|---|---|
 | |||
| Metabolite | [M + H]+ | Major Fragment Ions | Metabolic Pathway(s) |
| Saxagliptin | 316 | 180 | |
| M1 | 332 | 196 | Hydroxylation |
| 5-Hydroxy saxagliptin (M2) | 332 | 196 | Hydroxylation |
| M3 | 332 | 196 | Hydroxylation |
| M13 | 332 | 304, 196 | Hydroxylation, cyclization |
| M16 | 332 | 314, 196 | Hydroxylation |
| M45 | 396 | 298, 260 | Sulfation |
| M46 | 492 | 474, 316, 298 | Glucuronidation |
| D1 | 316 | 288, 180 | Cyclization |