The present invention relates to compositions, pharmaceutical compositions, and methods for preparing the same, comprising a tetracycline with improved stability and solubility. A voltage is applied between the bit line and the lower electrode so that current passes through the magnetoresistive cell. The method includes the steps of: forming a capacitor on a predetermined portion of a substrate; forming an insulation layer by stacking a flowable insulation layer and an undoped silicate glass layer on a resulting substrate structure including the substrate and the capacitor; and forming a metal interconnection line on the insulation layer.