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anhydrous, 96.0-102.0% (anhydrous basis)

Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


96.0-102.0% (anhydrous basis)



pKa (25 °C)

2.5 (COOH)
7.3 (NH2)


208 °C (dec.) (lit.)

Mode of action

cell wall synthesis | interferes

antibiotic activity spectrum

Gram-negative bacteria
Gram-positive bacteria

storage temp.


SMILES string




InChI key


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General description

Chemical structure: ß-lactam


Ampicillin 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

β-lactams are inactivated by β-lactamases and for this reason ampicillin is used with a β-lactamase inhibitor.
Mode of Action: Ampicillin is a semisynthetic penicillin and 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: Effective against 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. 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.

Other Notes

Store under argon. Keep container tightly closed in a dry and well-ventilated place, hygroscopic.


Exclamation markHealth hazard



Hazard Classifications

Eye Irrit. 2 - Resp. Sens. 1 - Skin Irrit. 2 - Skin Sens. 1 - STOT SE 3

Target Organs

Respiratory system

Storage Class Code

11 - Combustible Solids

WGK Germany


Flash Point F

Not applicable

Flash Point C

Not applicable

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves

Certificate of Analysis

Certificate of Origin

  1. Which document(s) contains shelf-life or expiration date information for a given product?

    If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.

  2. Is Ampicillin product stable in solution?

    We recommend using freshly prepared solutions. A concentrated solution of sodium ampicillin in water (approximately 330 mg/mL) may be expected to lose about 10% potency in 20 hours at -20°C.

  3. How do I use Ampicllin in agar plates?

    For plates, add ampicillin to autoclaved media cooled to 48°C, to a final concentration of 35-50 μg/mL. Pour the plates, and allow them to cool completely. Plates may be stored at 2-8°C for up to only 1-2 weeks before use.

  4. How do I get lot-specific information or a Certificate of Analysis?

    The lot specific COA document can be found by entering the lot number above under the "Documents" section.

  5. What is the solubility of Product A9393, Ampicillin?

    The solubility of ampicillin is tested at 50 mg/mL in 1M ammonium hydroxide. Additional solubility information can be found on the product information sheet (under Documents, above).

  6. Which Ampicillin product has higher water solubility, Product A9393 or Product A9518?

    Product No. A9518 (Ampicillin, sodium salt) is soluble at 50 mg/mL in water.

  7. How do I find price and availability?

    There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers.

  8. What is the Department of Transportation shipping information for this product?

    Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product. 

  9. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

Comparative evaluation of a new beta-lactamase inhibitor, YTR 830, combined with different beta-lactam antibiotics against bacteria harboring known beta-lactamases.
Antimicrobial Agents and Chemotherapy, 29, 955-957 (1986)
M R Jacobs et al.
Antimicrobial agents and chemotherapy, 29(6), 980-985 (1986-06-01)
The in vitro synergistic activities of the beta-lactamase inhibitors YTR 830, clavulanate, and sulbactam, combined with ampicillin, ticarcillin, mezlocillin, azlocillin, piperacillin, and apalcillin, were determined against 34 strains of members of the Enterobacteriaceae family, Pseudomonas aeruginosa, Aeromonas hydrophila, and Haemophilus...
Laurent Poirel et al.
Antimicrobial agents and chemotherapy, 52(5), 1613-1617 (2008-02-27)
The basis of the beta-lactam resistance of 39 multidrug-resistant Acinetobacter baumannii isolates recovered from hospitalized patients was studied. These isolates were collected from 2001 to 2005 at the Sahloul Hospital in Sousse, Tunisia. They belonged to two distinct clones. One...
Ritu Banerjee et al.
Antimicrobial agents and chemotherapy, 54(11), 4900-4902 (2010-09-02)
We previously generated a ceftobiprole-resistant Staphylococcus aureus strain after high inoculum serial passage of a mecA-negative variant of strain COL (R. Banerjee, M. Gretes, L. Basuino, N. Strynadka, and H. F. Chambers, Antimicrob. Agents Chemother. 52:2089-2096, 2008). Genome resequencing of...
Delphine Girlich et al.
Antimicrobial agents and chemotherapy, 54(1), 328-332 (2009-11-11)
A Pseudomonas fluorescens isolate (PF-1) resistant to carbapenems was recovered during an environmental survey performed with water from the Seine River (Paris). It expressed a novel Ambler class A carbapenemase, BIC-1, sharing 68 and 59% amino acid identities with beta-lactamases...

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