The present invention relates to solid pharmaceutical compositions, in particular to oral contraceptives, comprising a progestogen, such as drospirenone； an estrogen, such as ethinylestradiol； a tetrahydrofolic acid or a pharmaceutically acceptable salt thereof, such as calcium 5-methyl-(6S)-tetrahydrofolate； and at least one pharmaceutical acceptable excipient or carrier. The compositions of the invention provide good stability of the tetrahydrofolic acid upon storage while still ensuring a fast and reliable release of the estrogen and the progestogen present in the composition.本發明係關於固體醫藥組合物，尤其係關於口服避孕藥，其包含孕激素，諸如屈螺酮(drospirenone)；雌激素，諸如炔雌醇；四氫葉酸或其醫藥學上可接受之鹽，諸如5－甲基－(6S)－四氫葉酸鈣；及至少一種醫藥學上可接受之賦形劑或載劑。本發明之組合物在儲存時提供四氫葉酸之良好穩定性同時仍確保組合物中所存在之雌激素及孕激素之快速及可靠釋放。
