Growing data suggest that the antibiotic azithromycin mediates anti-inflammatory activity through the inhibition of the transcription factor NF-kappaB. The purpose of this study was to compare azithromycin's anti-inflammatory potency with that of hydrocortisone and dexamethasone as measured in an activated NF-kappaB assay. Dose-response curves and the corresponding inhibitory potencies (IC(50)) of azithromycin, hydrocortisone, and dexamethasone were evaluated in a fluorescence assay using A549 cells. All three compounds inhibited TNFalpha stimulated NF-kappaB activity in a dose-dependent manner. IC(50) values of azithromycin, hydrocortisone and dexamethasone were 56 microM, 2.6 nM, and 0.18 nM, respectively. Hydrocortisone was approximately 4 orders of magnitude more potent than azithromycin, while dexamethasone was approximately 14 times as potent as hydrocortisone. In relative terms the anti-inflammatory potency of azithromycin was about 4 orders of magnitude weaker than that of hydrocortisone.

The title compound 3-carboxyisoxazole 3 was synthesized by cycloaddition of carbethoxyformonitrile oxide to N-[4-(trifluoromethyl)phenyl]-3-pyrrolidino-2-butenamide (6) with spontaneous elimination of pyrrolidine followed by hydrolysis of the ethyl ester. Compound 3 was shown to be absorbed intact after oral administration to rats. Over 24 h, the compound was metabolized to yield plasma concentrations of the antiinflammatory agent 2-cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide (2), similar to those obtained following an equivalent dose of the established prodrug of 5-methyl-N-[4-(trifluoromethyl)phenyl]isoxazole-4-carboxamide (1).

5-Acyl-1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carboxylic acids and the homologous pyridine and azepine derivatives were synthesized and assayed for antiinflammatory and analgesic activity. 5-Benzoyl-1,2-dihydro-3H-pyrrolo-[1,2-a]pyrrole-1-carboxylic acid and the corresponding p-methoxy compound 74 were selected for evaluation as analgesic agents in humans on the basis of their high potency in the mouse phenylquinone writhing assay as well as on their minimal liability to elicit gastrointestinal erosion in rats on chronic administration. Extensive quantitative structure-activity relationship (QSAR) studies of the benzoylpyrrolopyrrolecarboxylic acids have demonstrated that the analgesic (mouse writhing) and antiinflammatory (rat carrageenan paw) potencies of these compounds are satisfactorily correlated with the steric and hydrogen-bonding properties of the benzoyl substituent(s). The 4-vinylbenzoyl compound 95, which was correctly predicted to be highly active in both assays on this basis, is undergoing advanced pharmacological evaluation in animals as a potential antiinflammatory agent.

The PK/PD profile of 2% azithromycin suggests efficacy against common causative bacteria with just one dose per day for three days.

5-Aroyl-6-substituted-1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carbo xylic acids were synthesized and assayed for analgesic and antiinflammatory activity. Several of these compounds, notably the 5-(4-fluoro- and 4-chlorobenzoyl)-6-methyl derivatives 25 and 26 and the 5-(4-methyl-, 4-fluoro-, 4-chloro-, and 4-methoxybenzoyl)-6-chloro congeners 31-34 were of equal or greater potency than indomethacin as antiinflammatory and analgesic agents both in acute and chronic animal models.