composition thus obtained was allowed to stand for 10 days at 50 u00b0 c and thereafter the remained percentage of the prostaglandin e group was measured the results are shown in the following table table 3______________________________________ addi ex prostaglandin e tion remainedno group additive amount percentage______________________________________15 a16 s methyl 20 deoxycholic 60 g 99 methoxy pge sub 2 vi acid arginine salt16 a vi dextran 70 120 g 85 17 a vi glutathione 40 g 93 18 a vi dextrin 100 g 92 19 a vi hydroxypropyl 20 g 84 methylcellulosecon vi none 0 38 trolcon vi mannitol 111 g 25 trol______________________________________ formulations having the compositions shown in table 4 were prepared using the prostaglandin containing powders referred to as pg powder obtained in aforesaid examples 15 a to 19 a and also the remained percentages of the prostaglandin e groups in the formulations were determined by the same manner as above the results are shown in the following table in a two liter vessel was placed a solution of 100 mg of the crystals of 16 methyl prostaglandin e 2 in 1 ml of ethanol and after wetting the wall of the vessel with the solution ethanol was distilled off from the solution under reduced pressure or nitrogen gas stream then 400 g of dextran 20 mean molecular weight of 20 000 and 1500 ml of distilled water were added to the residue to dissolve the solid components and after adding thereto distilled water to make the total amount thereof to 2 000 ml the solution was lyophilized in a two liter vessel was placed.