| abstract |
(57) [Problem] To provide a solid gabapentin preparation excellent in storage stability. And (i) crystalline anhydrous gabapentin as an active ingredient, containing less than 0.5% by weight of the corresponding lactam and less than 20 ppm of mineral acid anions; (ii) at 25 ° C. and 50% atmospheric humidity Stable and dry unit dosage form containing one or more pharmaceutically acceptable adjuvants, which does not promote the conversion of gabapentin to the corresponding lactam by more than 0.2% by weight when stored for one year Pure pharmaceutical composition. |