PROBLEM TO BE SOLVED: To provide a novel crystal polymorphism of levonorgestrel which is useful as an emergency contraceptive or the like, and to provide a production method thereof, as well as to provide a pharmaceutical composition.SOLUTION: The invention provides an α-crystal polymorphism of levonorgestrel in which a diffraction angle 2θ has a diffraction peak at 2θ=17.2° ±0.2°, 18.6° ±0.2°, 22.7° ±0.2°, 31.1° ±0.2°, and 35.5° ±0.2° in powder X-ray diffraction spectrum. When the strength of the diffraction peak at 2θ=18.6° ±0.2° is X2, and the strength of the diffraction peak at 2θ=31.1° ±0.2° is X4, the intensity ratio X4/X2 of X2 and X4 is 25/100-400/100. The invention also provides a method for producing the α-crystal polymorphism by mixing a dioxane solution of levonorgestrel with a mixed solvent that contains water and dioxane in a weight ratio of water/dioxane=50/0-95/5.COPYRIGHT: (C)2016,JPO&INPIT【課題】緊急避妊薬などとして有用なレボノルゲストレルの新規結晶多形及びその製造方法、並びに医薬組成物の提供。【解決手段】粉末Ｘ線回折スペクトルにおいて、回折角度２θが、２θ＝１７．２°±０．２°，１８．６°±０．２°，２２．７°±０．２°，３１．１°±０．２°及び３５．５°±０．２°の角度に回折ピークを有し、２θ＝１８．６°±０．２°での回折ピークの強度をＸ２、２θ＝３１．１°±０．２°での回折ピークの強度をＸ４としたとき、Ｘ２とＸ４との強度比Ｘ４／Ｘ２が２５／１００～４００／１００であるレボノルゲストレルの結晶多形α。前記結晶多形αを、レボノルゲストレルのジオキサン溶液と、水とジオキサンとを水／ジオキサン＝５０／０～９５／５の重量比で含む混合溶媒と、を混合することにより製造する方法。【選択図】なし
