EXHIBIT 99.1 Amphastar Pharmaceuticals Reports Financial Results for the Three Months Ended March 31, 2025 Reports Net Revenues of $170.5 Million for the Three Months Ended March 31, 2025 RANCHO CUCAMONGA, CA – May 7, 2025 – Amphastar Pharmaceuticals, Inc. (NASDAQ: AMPH) ("Amphastar" or the "Company") today reported results for the three months ended March 31, 2025. * Adjusted non-GAAP net income and adjusted non-GAAP diluted EPS are non-GAAP financial measures. Please see the discussion in the section enti ...