A study of the decomposition of the pyrazoline bisphosphonate ester 2 identified 3 as the sole bisphosphonate component. Evaluation in a delayed-type hypersensitivity granuloma model of chronic inflammation in mice (DTH-GRA) showed 3 to be a potent inhibitor of granuloma formation (sc, 10 mg/kg, 45%), but in a murine model of antigen-induced arthritis (AIA), no significant inhibition was observed. As a result, new ketonic bisphosphonate ...