Metabolism of the antimicrobial agent nibroxane, 5-bromo-2-methyl-5-nitro-m-dioxane, in the rat.

1. The metabolism of nibroxane, a topically effective antimicrobial agent has been studied in the rat after oral and dermal administrations. 2. Plasma level studies in vitro and in vivo showed nibroxane to be rapidly debrominated to 2-methyl-5-nitro-m-dioxane. 3. Nibroxane is rapidly absorbed and extensively metabolized in the rat regardless of the route of administration. 4. Enzymic hydrolysis of the m-dioxane ring was of major importance in the biotransformation of nibroxane. The major eliminated metabolite in the rat was 2-nitropropan-1,3-diol.