Sparingly soluble salts of streptomycin antibiotics with acyl-embonic acids the acyl being derived from a 2-5C aliphatic acid, are used as antitubercular depot cpds. which obviate frequent i.m. injections and ensure even serum levels. The acetyl-embonates of streptomycin and dihydrostreptomycin are preferred. In the process the streptomycin as water-sol. salt or a complex is reacted in known manner with an acylembonic acid as water-sol. salt or as DMF adduct. Good yields are obtained.
