Crystalline 1 (TAK-599) is a novel N-phosphono prodrug of anti-methicillin-resistant Staphylococcus aureus (MRSA) cephalosporin 2a (T-91825) that has high affinity for penicillin-binding protein (PBP) 2′(IC50; 0.90 μg/mL) and shows potent in vitro anti-MRSA activity (MIC against MRSA N133; 1.56 μg/mL), comparable to that of vancomycin (1.56 μg/mL). Although 2a had insufficient water solubility (2.3 mg/mL) for parenteral ...