Freeze-dried pharmaceutical preparation

For clinical application of cis[((1R,2R)-1,2-cyclohexanediamine-N,N′)bis(R 1 )]platinum(II) (R 1 is an alkanoyloxy group having 6 to 20 carbon atoms), the present invention aims at providing a formulation which prevents layer separation and changes in viscosity, shows fine suspendability, and which is easy to handle during administration. The formulation of the present invention is a lyophilized formulation for injection obtained by dissolving a cis[((1R,2R)-1,2-cyclohexanediamine-N,N′)bis(R 1 )]platinum(II) in 2-methyl-2-propanol and lyophilizing this solution, which has a central particle size distribution of around 3-25 μm and a D90% value of not more than 40 μm.