AHR-10037, a non-steroidal anti-inflammatory compound of low gastric toxicity.

AHR-10037 is an anti-inflammatory compound possessing analgesic and antipyretic properties and a high therapeutic index. AHR-10037 was comparable to indomethacin in suppressing acute (Evans blue-carrageenan pleural effusion) and chronic (adjuvant-induced arthritis) inflammation. There was a delayed onset of antipyresis (yeast-induced hyperthermia in rats), analgesia (acetylcholine-induced abdominal constriction in mice) and inhibition of caster oil-induced diarrhea in rats. Antipyresis occurred 3 hours after administration of AHR-10037, 4 mg/kg, PO. vs 1 hour after administration of acetylsalicylic acid, 100 mg/kg, PO; maximum analgesic activity (ED50 = 4.1 mg/kg) occurred at 4 hours. AHR-10037 was inferior to indomethacin in suppressing castor oil-induced diarrhea in rats. The therapeutic index of AHR-10037 (relating acute anti-inflammatory potency to gastric toxicity potency relative to indomethacin) ranged from 56-91. The pharmacological profile suggests that AHR-10037 is a prodrug converted in vivo to a cyclooxygenase inhibitor.

AHR-15010--a novel anti-arthritic agent.

AHR-15010 (3-(2-methoxyphenoxy)-1,2-propanediol bissulphamate ester) is a compound of novel structure that displays anti-arthritic activity in adjuvant arthritis in rats. When given orally from days 18 through day 50, (excluding weekends) after adjuvant injection, AHR-15010, at doses of 3.16 to 100 mg kg-1, produced significant anti-inflammatory activity and reduced the severity of the hind paw joint lesions as monitored by X-ray analysis. AHR-15010, however, has no acute anti-inflammatory activity in the Evans Blue-carrageenan pleural effusion assay in rats, has no analgesic activity in mice, and has no activity in a classic, delayed-type, hypersensitivity assay in mice or in a cotton pellet granuloma test in rats. These data, in conjunction with biochemical data showing that AHR-15010 has no prostaglandin synthetase inhibiting activity suggest that AHR-15010 is an anti-arthritic with a unique mechanism of action. AHR-15010 is a carbonic anhydrase inhibitor. Data are presented that suggest that AHR-15010 and acetazolamide, a prototype carbonic anhydrase inhibitor, may present novel approaches to the treatment of arthritis.

The topical anti-inflammatory and analgesic properties of bromfenac in rodents.

Bromfenac [2-amino-3-(4-bromobenzoyl)benzeneacetic acid sodium salt sesquihydrate] is an anti-inflammatory/analgesic agent that possesses potent topical activity in rats, guinea pigs, and mice. In rat models of acute (carrageenan paw edema) and chronic (adjuvant arthritis) inflammation, preparations of bromfenac at concentrations as low as 0.01-0.32% (0.01-0.32 mg bromfenac) produced significant anti-inflammatory activity when applied to the injected paw or to the backs of rats. In the acute paw edema test, topical bromfenac was more potent than indomethacin or hydrocortisone and about as active as triamcinolone acetonide. Bromfenac, at concentrations of 0.1-0.32%, showed topical analgesic activity in the acetylcholine-induced abdominal constriction test in mice. In this test, bromfenac was more potent than indomethacin (24.9X), more potent than ketoprofen (approximately 14.9X), and superior to piroxicam. In the guinea pig UV-erythema test, bromfenac was active (26.1X indomethacin) when applied to the UV-exposed site, but not when applied away from the site. The results suggest that bromfenac has activity topically because of a local and a systemic effect. Test results obtained with a long (4-7 hr) pretreatment time (paw edema, adjuvant arthritis, abdominal constriction) are due in great part to a systemic effect of topically applied bromfenac, while the UV-erythema test (1-hr treatment time) clearly indicates a local effect.