The purpose of the present invention is to provide a novel injection that has excellent sustained drug-release properties. An injection comprising a hardly water soluble drug, gellan gum and a solvent, wherein the solvent is dimethyl sulfoxide or a solvent mixture consisting of dimethyl sulfoxide and water.本發明提供一種藥物之緩釋性優異之新型注射劑。本發明係一種含有水難溶性藥物、結冷膠(gellan gum)及溶劑之注射劑,且該溶劑係二甲基亞碸或二甲基亞碸與水之混合溶劑。