The invention relates to novel liquid preparation comprising a substituted benzimidazol, preferably pimobendan as pharmaceutically active compound. In particular, the present invention relates to liquid preparation comprising an etherified cyclodextrin derivative, preferably in a concentration of about 20 to 70% (w/v) and said substituted benzimidazol, preferably in a concentration of about 0.005 to 0.15 % (w/w).本發明係關於包含經取代之苯幷咪唑(較佳為匹莫苯坦(pimobendan))作為醫藥活性化合物的新穎液體製劑。詳言之,本發明係關於包含醚化環糊精衍生物(較佳約20%至70%(w/v)濃度)及該經取代苯幷咪唑(較佳約0.005%至0.15%(w/w)濃度)的液體製劑。