Table 2
Mass spectrometric analysis of irbesartan and its metabolites isolated from human urine
| Sample | Emp. Formula | Mol. Wt. | Exact Massa,b | Calc. Mass2-a | Δ PPM | Relevant Ions m/z(Relative Intensity)2-c | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| (M + H+) | A | B or A − N2 | C | A − HN3 | B − NH3 | ||||||
| Irbesartan | C25H28ON6 | 428 | ND | ND | ND | 429 (8) | 235 (6) | 207 (100) | 195 (8) | 192 (8) | 180 (7) |
| M1 | C25H28O3N6 | 460 | 461.2301 | 461.2301 | 0 | 461 (10) | 235 (5) | 207 (100) | 227 (8) | 192 (6) | 180 (5) |
| M2 | C25H26O3N6 | 458 | 459.2133 | 459.2145 | −2.6 | 459 (18) | 235 (6) | 207 (100) | 225 (4) | 192 (5) | — |
| M3 | C25H26O3N6 | 458 | 459.2148 | 459.2145 | +0.8 | 459 (8) | 235 (13) | 207 (100) | 225 (10) | 192 (6) | 180 (6) |
| M4 | C25H28O2N6 | 444 | 445.2372 | 445.2352 | +4.6 | 445 (8) | 235 (4) | 207 (100) | 211 (11) | 192 (9) | 180 (6) |
| M5 | C25H28O2N6 | 444 | 445.2350 | 445.2352 | −0.3 | 445 (24) | 235 (8) | 207 (100) | 211 (7) | 192 (5) | 180 (4) |
| M6 | C25H26O2N6 | 442 | 443.2183 | 443.2195 | −2.8 | 443 (27) | 235 (10) | 207 (100) | 209 (14) | 192 (5) | 180 (3) |
| M7 | C25H28O2N6 | 444 | 445.2341 | 445.2352 | −2.5 | 445 (27) | 235 (8) | 207 (100) | 211 (11) | 192 (8) | 180 (4) |
| M8 | C31H36O7N6 | 604 | 605.2744 | 605.2724 | +3.3 | 605 (28) | 235 (41)2-d | 207 (20)2-d | — | 192 (40)2-d | — |
| M9 | C25H28ON6 | 428 | 429.2399 | 429.2403 | −0.9 | 429 (7) | 235 (6) | 207 (100) | 195 (7) | 192 (11) | 180 (7) |
-
↵2-a Mass of the protonated molecular ion (M + H+); ND = not determined.
-
2-b These results were obtained using fast atom bombardment spectrometry.
-
↵2-c These MS/MS results were obtained using ion spray mass spectrometry.
-
↵2-d Additional product ions of m/z 429 (13), 386 (85), 383 (100), 365 (29), 347 (3), 319 (5), 277 (8), and 249 (8) were generated by M8.