TRK-530 is a novel bisphosphonate derivative. We examined the anti-inflammatory effects of TRK-530 on adjuvant arthritis (AA) rats. When TRK-530 at a dose of 2.5 mg/kg was administered for 2 weeks to AA rats, it inhibited destructive changes in arthritic joints such as paw edema, bone loss and joint degeneration. TRK-530 also inhibited splenomegaly and suppressed the increase in serum sialic acid which is measured as a systemic parameter of inflammation. To clarify the inhibitory mechanism of TRK-530, interleukin-1 (IL-1)-like activities of resident peritoneal macrophages in AA rats given TRK-530 were compared with those of control rats. We found that TRK-530 inhibited IL-1-like activity induced by bacterial lipopolysaccharide 6 weeks after administration when the IL-1-like activities of control rats were still at high levels. These findings suggest that TRK-530 exerts anti-inflammatory activities in AA rats.

TRK-530 is a novel synthetic bisphosphonate compound which exhibits inhibitory activity in the rat adjuvant arthritis (AA) model. We found that, during AA development, the concentrations of cytokine-induced neutrophil chemoattractant-1 (CINC-1) and tumor necrosis factor α (TNF-α) in the bone marrow increased, and that administration of TRK-530 decreased the concentrations of these cytokines. The suppression of these concentration increases paralleled the inhibition of paw edema. Paw edema inhibition by TRK-530 in rat AA may be the result of decreasing CINC-1 and TNF-α concentrations.

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TRK-530, a newly synthesized bisphosphonate, was assessed for its effects on the accumulation of superoxide anions derived from human formyl-methionyl-leucyl-phenylalanine-stimulated polymorphonuclear leukocytes (PMN), and for its effects on bone resorption using a pit formation assay. TRK-530 concentration-dependently inhibited superoxide accumulation derived from PMN and osteoclast pit formation stimulated by 1,25-dihydroxyvitamin D₃. Incadronate and risedronate had a strong inhibitory effect on pit formation, but no antioxidative activity. These data suggest that the anti-bone resorption activities of TRK-530 are possibly unrelated to its antioxidant properties. However, it is difficult to conclude at present which mechanisms play the most important role in the anti-bone resorption activities of TRK-530.

Reactions of 1-halo-1-nitroso- and 1-halo-1-nitrocycloalkanes with triphenylphosphine have been carried out. The Perkov reaction and Beckmann rearrangement occurred successively with the formation of lactams in high yields. The reaction of cycloalkanone oxime with halogen in the presence of triphenylphosphine also gave lactams in one step.