Form
Powder
Appearance
White or almost white powder
Source
Semi-synthetic
Water Content (Karl Fisher)
≤10.0%
Melting Point
196-197°C (dec.)
Optical Rotation
+225°
Assay
≥90.0%
Methicillin sodium is a narrow spectrum β-lactam antibiotic in the penicillin family and is soluble in aqueous solution (0.3 mg/mL).
132-92-3
C17H19N2NaO6S
402.40
β-lactams interfere with PBP (penicillin binding protein) activity involved in the final phase of peptidoglycan synthesis. PBP’s are enzymes which catalyze a pentaglycine crosslink between alanine and lysine residues providing additional strength to the cell wall. Without a pentaglycine crosslink, the integrity of the cell wall is severely compromised and ultimately leads to cell lysis and death. Resistance to β-lactams is commonly due to cells containing plasmid encoded β-lactamases. Methicillin is mostly resistant to β-lactamases.
-20°C
2941.10.5000
Methicillin targets primarily the cell wall of Gram positive organisms especially Staphylococcus aureus.
Powder
White or almost white powder
Semi-synthetic
≤10.0%
196-197°C (dec.)
+225°
≥90.0%