TABLE 6
Summary of omeprazole metabolites in human plasma detected by the MDF method
Peak in LC/MSa | MH+ | Major Fragment Ionb | Molecular Formula | Δ MW from Omeprazole | Δ MD from Omeprazole | Structure Identified |
|---|---|---|---|---|---|---|
| Ec | 305 | -37 | +0.0040 | Endogenous compound | ||
| M1 | 362 | 214 | C17H19N3O4S | +16 (+O) | -0.0051 | Mono-oxidation metabolite |
| M2 | 316 | 168 | C16H17N3O2S | -30 (-O, -CH2) | +0.0100 | A product from reduction and demethylation |
| M3 | 362 | 214 | C17H19N3O4S | +O (+16) | -0.0051 | Mono-oxidation metabolite |
| Drug | 346 | 198 | C17H19N3O3S | 0 | Parent drug | |
| M4 | 330 | 182 | C17H19N3O2S | -O (-16) | +0.0051 | A reduction product |
| M5 | 362 | 214 | C17H19N3O4S | +O (+16) | -0.0051 | Mono-oxidation metabolite |
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↵a Peaks displayed on the TIC (Fig. 7B) of omeprazole metabolites in human plasma after MDF processing using the parent drug as a template.
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↵b The fragment ions presented here were obtained from an omeprazole HLM sample acquired using Q-ToF LC/MS with a collision energy of 16 eV.
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↵c The peak was assigned as an endogenous component on the basis of the protonated molecule at m/z 305 and consideration of the possible empirical formulae.