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A0166 Sigma-Aldrich

Ampicillin sodium salt

powder, BioReagent, suitable for cell culture

Synonym: D-(−)-α-Aminobenzylpenicillin sodium salt

  • CAS Number 69-52-3

  • Empirical Formula (Hill Notation) C16H18N3NaO4S

  • Molecular Weight 371.39

  •  Beilstein Registry Number 4119211

  •  EC Number 200-708-1

  •  MDL number MFCD00064313

  •  PubChem Substance ID 24890405



Related Categories A - K, Antibacterial, Antibiotics, Antibiotics A to Z, Antibiotics by Application,
biological source   synthetic
product line   BioReagent
form   powder
potency   ≥845 μg per mg
color   white to slight yellow
mp   215 °C (dec.) (lit.)
solubility   H2O: 50 mg/mL (Stock solutions should be stored at −20 °C.)
suitability   suitable for cell culture
Mode of action   cell wall synthesis | interferes
antibiotic activity spectrum   Gram-negative bacteria
  Gram-positive bacteria
storage temp.   2-8°C



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.

Recommended for antibacterial use in cell culture media at 100 mg/L.
Recommended for use in ampicillin-resistance studies at 20-125 μg/ml.

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.


This product has been reported stable as supplied at 25°C at 43% and 81% relative humidity for six weeks. It is stable at 37°C for three days. 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.


5g, 25g, 100g

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.

General description

Chemical structure: ß-lactam

Other Notes

Keep container tightly closed in a dry and well-ventilated place. Keep in a dry place.

Safety & Documentation

Safety Information

GHS08  GHS08
Signal word 
Hazard statements 
Precautionary statements 
Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 

Cell Culture Guide

Milli-Q® Water Purification Solutions
Protocols & Articles


USP HPLC Analysis of Ampicillin Sodium on Ascentis® Express C18

From our library of Articles, Sigma-Aldrich presents USP HPLC Analysis of Ampicillin Sodium on Ascentis® Express C18
Keywords: Antibiotics, Chromatography, High performance liquid chromatography, Pharmaceutical

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