Abstract: The invention relates to new N-hydroxy-4-(3-phenyl-5-methyl-isoxazole-4-yl)-benzenesulfonamide solvates of formula (I). wherein n represents 0 or 1 mol, [solvate] represents water, C1-C4 alcohol, C1-C4 alkylester of C1-C3 carboxylic acid or dioxane, and the mixture of solvated (wherein n=1) and solvat-free forms (wherein n=0). Furthermore, the invention relates their process for production and use for the treatment of osteoarthritis and rheumatoid arthritis and surgical and primary dysmenorrheal pains, based on anti-inflammatory and analgesic pharmacological model experiments.