PURPOSE: To obtain a lyophilized pharmaceutical preparation having no reduction in titer even if it is preserved at high temperature with time, obtained by blending a specific carbapenem derivative with a stabilizer such as urea, nicotinic acid amide, etc.

CONSTITUTION: (5R,6S,8R)-2[(3S)-1-Acetamidoylpyrrolidin-3-ylthio]-6-(1-hydroxy e-thyl-)--2-carbapenem-3-carboxylic acid or its salt and a stabilizer selected from urea, nicotinic acid amide, N-acetylglucosamine, and N-acetylglycine are dissolved in water, bacteria are removed by filtration, a fixed amount of the solution is then partially added to vials or ampules, lyophilized, the vials or the ampules are closed with stoppers or closed in a molten state, to give a lyophilized pharmaceutical preparation. An amount of the stabilizer blended is ≥0.25mol base on 1 mol compound shown by the formula, especially prefer ably about equimolar amount.