Microcrystals of (E)-8-(3,4-dimethoxystyryl)-1,3-diethyl-7-methyl-3,7-dihydro-1H-purine-2,6-dione having an average particle size of less than 50 μm; microcrystals of (E)-8-(3,4-dimethoxystyryl)-1,3-diethyl-7-methyl-3,7-dihydro-1H-purine-2,6-dione having an average particle size of less than 50 μm and a crystallinity of 20% or more or the like, which possess excellent solubility, stability, bioavailability, dispersing property in a pharmaceutical formulation; and the like are provided. A solid pharmaceutical formulation which is characterized by comprising the same is also provided.
1. Microcrystals of (E)-8-(3,4-dimethoxystyryl)-1,3-diethyl-7-methyl-3,7-dihydro-1H-purine-2,6-dione represented by the following formula
wherein the average particle size of the microcrystals is less than 50 μm.
2. The microcrystals according to claim 1 , wherein the average particle size of the microcrystals is 0.5 to 20 μm.
3. A solid pharmaceutical formulation comprising the microcrystals according to claim 1 or 2 , and a pharmaceutically acceptable carrier.
4. The microcrystals according to claim 1 or 2 , which are obtained by pulverization using a jet mill of crystals of (E)-8-(3,4-dimethoxystyryl)-1,3-diethyl-7-methyl-3,7-dihydro-1H-purine-2,6-dione, said crystals having an average particle size of not less than 50 μm.
5. The solid pharmaceutical formulation according to claim 3 , wherein the microcrystals are obtained by pulverization using a jet mill of crystals of (E)-8-(3,4-dimethoxystryl)-1,3 -diethyl-7-methyl-3,7-dihydro-1H-purine-2,6-dione, said crystals having an average particle size of not less than 50 μm.