Abstract: Objective: To study the anti-inflammatory activity and tissue distribution patterns of intravenous emulsion of dexamethasone acetate in mice. Methods: The anti-inflammatory solution for injection and Limethasone (Jepanese product) given intravenously were evaluated by using the preformed carrageenan granuloma pouch method in rats. Results: The anti-inflammatory activity of dexamethasone acetate emulsion at low dose of 0.05 mg·kg^-1 was as potent as dexamethasone sodium phosphate solution at high dose of 0.3 mg·kg^-1. The distribution patterns in mice tissues of [³H]dexamethasone acetate emulsion and [³H]dexamethasone sodium phosphate solution in mice were markedly different. Dexamethasone acetate emulsion showed a much higher concentration in the liver, spleen, lung, and inflamed tissues, whereas dexamethasone sodium phosphate had a high concentration in the muscles of vastus lateralis. These results may indicate that dexamethasone incoporated in lipid emulsion was taken up by the reticuloendothelial system and inflammatory cells much more than dexamethasone sodium phosphate solution. Conclusion: When dexamethasone acetate was incorporated in emulsion, the distribution patterns in tissues were changed and they had a stronger anti-inflammatory activity.

Key words: Anti-inflammatory activity, Tissues distribution, Intravenous emulsion