There exists a strong desire both for pharmaceutical compositions which rapidly exhibit pharmacological effects without an increase in the size of the dosage form or a decline in quality due to interactions between a pharmaceutically active ingredient and the disintegrant, and also for a method of preparing such pharmaceutical compositions. Such a desire is especially acute with regard to, for example, preparations which contain a drug such as an analgesic or a quick-acting hypoglycemic drug that requires the rapid appearance of pharmacological effects following administration, preparations which have a high content of the pharmaceutically active ingredient, and preparations which contain two or more different active pharmaceutical ingredients. Thus, the object of the present invention is to improve the disintegratability of the pharmaceutical compositions without increasing the size of the dosage form and without a decline in quality due to interactions between the pharmaceutically active ingredient and the disintegrant. The present invention provides a method for preparing a pharmaceutical composition having a rapid disintegration time, comprising: blending, in the pharmaceutical composition containing a pharmaceutically active ingredient, at least one disintegrant and at least one water-soluble salt having a pH being from 3 to 9 in an aqueous solution of 2.5% concentration. The invention also provides a premix composition obtained by the preliminary mixture of a disintegrant with a water-soluble inorganic salt having a pH being from 3 to 9 in an aqueous solution of 2.5% concentration.
