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
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to treat inflammation and to provide pain relief but suffer from a major liability concerning their propensity to cause gastric damage. As nitric oxide (NO) is known to be gastro-protective we have synthesized a NO-donating prodrug of naproxen named NMI-1182. We evaluated two cyclo-oxygenase (COX)-inhibiting nitric oxide donors (CINODs), NMI-1182 and AZD3582, for their ability to be gastro-protective compared to naproxen and for their anti-inflammatory activity. NMI-1182 and AZD3582 were found to produce similar inhibition of COX activity to that produced by naproxen. Both NMI-1182 and AZD3582 produced significantly less gastric lesions after oral administration than naproxen. All three compounds effectively inhibited paw swelling in the rat carrageenan paw edema model. In the carrageenan air pouch model all three compounds significantly reduced PGE2 levels in the pouch exudate but only NMI-1182 and naproxen inhibited leukocyte influx. These data demonstrate that NMI-1182 has comparable anti-inflammatory activity to naproxen but with a much reduced likelihood to cause gastric damage.
Subject(s)
Cyclooxygenase Inhibitors/pharmacology , Naphthalenes/pharmacology , Nitric Oxide Donors/pharmacology , Protective Agents/pharmacology , Animals , Anti-Inflammatory Agents/blood , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Aorta, Abdominal/drug effects , Aorta, Abdominal/physiology , Carrageenan , Cyclooxygenase 1/blood , Cyclooxygenase 2/blood , Cyclooxygenase Inhibitors/blood , Cyclooxygenase Inhibitors/chemistry , Dinoprostone/antagonists & inhibitors , Dinoprostone/metabolism , Dose-Response Relationship, Drug , Edema/chemically induced , Edema/prevention & control , Gastric Mucosa/drug effects , Gastric Mucosa/metabolism , Gastric Mucosa/pathology , Humans , In Vitro Techniques , Inflammation/chemically induced , Inflammation/prevention & control , Male , Molecular Structure , Naphthalenes/blood , Naphthalenes/chemistry , Naproxen/blood , Naproxen/chemistry , Naproxen/pharmacology , Neutrophil Infiltration/drug effects , Nitric Oxide Donors/blood , Nitric Oxide Donors/chemistry , Protective Agents/chemistry , Rats , Rats, Sprague-Dawley , Vasodilation/drug effectsABSTRACT
Cyclooxygenase (COX, EC 1.14.99.1) inhibitor-nitric oxide (NO) donor (CINOD) hybrid compounds represent an attractive alternative to NSAID and coxib therapy. This report compares two CINODs, NMI-1182 (naproxen-glyceryl dinitrate) and AZD3582 (naproxen-n-butyl nitrate), for their ability to inhibit COX-1 and -2, deliver bioavailable nitric oxide, and release naproxen, using in vitro biochemical and pharmacological methods. In human whole blood, both CINODs showed inhibition, comparable to naproxen, of both COX isozymes and slowly released naproxen. Both CINODs donated bioavailable NO, as detected by cGMP induction in the pig kidney transformed cell line, LLC-PK1, but NMI-1182 was more potent by 30-100 times than AZD3582, GTN, GDN, and ISDN and considerably faster in inducing cGMP synthesis than AZD3582. The nitrate groups of GTN, NMI-1182, and AZD3582 appeared to be bioactivated via a common pathway, since each compound desensitized LLC-PK1 cells to subsequent challenge with the other compounds. Similar cGMP induction also occurred in normal, untransformed cells (human renal proximal tubule epithelial cells and hepatocytes from man, rat, and monkey); again, NMI-1182 was superior to AZD3582. NMI-1182 was also the more metabolically labile compound, releasing more absolute nitrate and nitrite (total NO(x)) in human stomach (in which NO is salutary) and liver S9 homogenates. Naproxen was also more rapidly freed from NMI-1182 than AZD3582 in human stomach, although liver S9 hydrolyzed both CINODs with similar rates. These in vitro tests revealed that NMI-1182 may be a better CINOD than AZD3582 because of its superior NO donating and naproxen liberating properties.
