Ampicillin anhydrous, 96.0-100.5% (anhydrous basis)

Synonym: D-(−)-α-Aminobenzylpenicillin

CAS Number: 69-53-4

Empirical Formula (Hill Notation): C₁₆H₁₉N₃O₄S

Molecular Weight: 349.40

Beilstein Registry Number: 1090925

EC Number: 200-709-7

MDL Number: MFCD00005175

PubChem Substance ID: 24891442

Application
Ampicillin is a semi-synthetic derivative of penicillin that functions as a broad-spectrum antibiotic. It has been used to study antibiotic resistance and penetration limitations, the synergy between multiple antibiotics, certain bloodstream infections, and has been used to develop PCR assays to detect resistance genes in cerebrospinal fluid.

Biochem/physiol Actions
Mode of Action: This is a ß-lactam antibiotic that inhibits bacterial cell-wall synthesis by inactivating transpeptidases on the inner surface of the bacterial cell membrane.

Mode of Resistance: Administration with ß-lactamase cleaves the ß-lactam ring of Ampicillin and inactivates it.

Antimicrobial Spectrum:Includes both gram-positive (similar to benzylpenicillin) and gram-negative bacteria (similar to tetracyclines and chloramphenicol.

Caution
This product has been reported stable as supplied at 25°C at 43% and 81% relative humidity for six weeks. Additional studies have shown that the stability of Ampicillin in solution is a function of pH, temperature and the identity of the buffer. It′s activity is quickly lost when stored above pH 7. Optimal storage conditions are suggested as 2-8°C, and pH 3.8-5 where its activity was retained at 90%+ for a week.

Preparation Note
Ampicillin is reported as slightly soluble in water, practically insoluble in alcohol, chloroform, ether and fixed oils but soluble in dilute acids or bases. The solution should not be autoclaved; a stock solution should be sterilized through filtration and stored frozen, where it will be stable for months.