ABSTRACT
Indomethacin, a nonselective cyclooxygenase (COX) inhibitor, was modified in three distinct regions in an attempt both to increase cyclooxygenase-2 (COX-2) selectivity and to enhance drug safety by covalent attachment of an organic nitrate moiety as a nitric oxide donor. A human whole-blood COX assay shows the modifications on the 3-acetic acid part of the indomethacin yielding an amide-nitrate derivative 32 and a sulfonamide-nitrate derivative 61 conferred COX-2 selectivity. Along with their respective des-nitrate analogs, for example, 31 and 62, the nitrates 32 and 61 were effective antiinflammatory agents in the rat air-pouch model. After oral dosing, though, only 32 increased nitrate and nitrite levels in rat plasma, indicating that its nitrate tether served as a nitric oxide donor in vivo. In a rat gastric injury model, examples 31 and 32 both show a 98% reduction in gastric lesion score compared to that of indomethacin. In addition, the nitrated derivative 32 inducing 85% fewer gastric lesions when coadministered with aspirin as compared to the combination of aspirin and valdecoxib.
Subject(s)
Cyclooxygenase 2 Inhibitors/chemical synthesis , Indomethacin/analogs & derivatives , Indomethacin/chemical synthesis , Nitric Oxide Donors/chemical synthesis , Animals , Aspirin/adverse effects , Celecoxib , Cyclooxygenase 2 Inhibitors/adverse effects , Cyclooxygenase 2 Inhibitors/pharmacology , Drug Design , Drug Synergism , Female , Gastric Mucosa/pathology , Humans , Hydroxamic Acids/adverse effects , Hydroxamic Acids/chemical synthesis , Hydroxamic Acids/pharmacology , Indomethacin/adverse effects , Indomethacin/pharmacology , Male , Nitric Oxide Donors/adverse effects , Nitric Oxide Donors/pharmacology , Pyrazoles/pharmacology , Rats , Rats, Sprague-Dawley , Stomach Ulcer/chemically induced , Stomach Ulcer/pathology , Structure-Activity Relationship , Sulfonamides/pharmacologyABSTRACT
Nitric oxide (NO) enhances anti-inflammatory drug action. Through a metabonomics approach termed "NObonomics," the effects of a prototypic NO donor (organic nitrate)-cyclooxygenase-2 inhibitor hybrid (NO-coxib), NMI-1093, on the NO metabolite status of the circulation and major organs have been profiled in vivo in the rat. An oral anti-inflammatory NMI-1093 bolus elicited acute tissue-, time-, and dose-dependent changes in oxidative and nitroso/nitrosyl NO metabolites. Gastric N-nitrosation and hepatic S-nitrosation and heme nitrosylation emerged as sensitive indices of this NO-coxib's metabolism. Acute NMI-1093-induced nitros(yl)ation correlated positively as a function of nitrate plus nitrite formation across all organs examined, suggesting a unifying in vivo mechanism consequent to NMI-1093 biotransformation that links oxidative and nitros(yl)ative routes of NO chemical biology and thereby may support downstream NO signaling. NMI-1093 depressed erythrocyte nitros(yl)ation, likely by inhibiting cellular carbonic anhydrase and shifting the intracellular balance between nitrogen oxides and carbonates. Glutathione-S-transferase or cytochrome P450 inhibitors also attenuated NMI-1093's NO metabolism in a compartment-selective fashion. Although not itself a NO donor, the des-nitro coxib analog of NMI-1093 influenced basal NO metabolite profiles, implicating a cyclooxygenase-NO synthase interaction in physiological NO regulation. By detailing the global NO metrics of a unique coxib bearing a popular NO-donor pharmacophore (i.e., a nitrate moiety) and defining some critical mechanistic determinants, this study demonstrates how NObonomics can serve as valuable tool in helping elucidate NO systems biology and the effect of NO-donor and non-NO-donating therapeutics thereon.
