Ampicillin inhibits cell wall synthesis. Used to select for drug-resistant, plasmid-bearing bacteria.Potency:900-1050mcg/mg (C16H19N3O4S anhy.)Residual Solvents (Dimethyl aniline, GC):Conforms to standardSolubility (10mg/ml, H2O):Clear, colorless and complete with warming. Slightly soluble in water and in Methanol, insoluble in benzene, in carbon tetrachloride and in chloroformpH:3.5-6.0Crystallinity:Conforms to standardWater (KF):12.0-15.0%Working Concentration:20-50ug/ml for E. coliStorage and Stability:Powder may be stored at 4°C. Stable for 6 months after receipt.Meets or exceeds USP Specifications