The present invention provides a dissolution improved pharmaceutical composltlon contalnlng: (A) a compound of the following formula (I)or the pharmaceutically acceptable salt thereof, and (B) a low substituted hydroxypropylcellulose.本發明為提供含有如下式(I)化合物或其藥理容許鹽而改善溶出性之醫藥組成物,內含:(A)如下式(I)化合物或其藥理容許鹽,及(B)低取代度羥丙基纖維素。