Article: Ampicillin

Ampicillin
Systematic (IUPAC) name
7-(2-amino-2-phenyl-acetyl)amino-3,3 -dimethyl-6-oxo-2-thia-5-azabicyclo [3.2.0]heptane-4-carboxylic acid
Identifiers
CAS number	69-53-4
ATC code	J01CA01
PubChem	149171
DrugBank	APRD00320
Chemical data
Formula	C16H18N3O4S
Mol. weight	349.406 g/mol
Pharmacokinetic data
Bioavailability	40% (oral)
Protein binding	15 to 25%
Metabolism	?
Half life	approx 1 hour
Excretion	75 to 85% renal
Therapeutic considerations
Pregnancy cat.	A (Au), B (U.S.)
Legal status
Routes	Oral, intravenous

Ampicillin is a beta-lactam antibiotic that has been used extensively to treat bacterial infections since 1961. It can sometimes result in allergic reactions that range in severity from a rash to potentially lethal anaphylaxis.

Mechanism of action

Belonging to the group of beta-lactam antibiotics, ampicillin is able to penetrate Gram-negative bacteria. It inhibits the third and final stage of bacterial cell wall synthesis, which ultimately leads to cell lysis.

Indications

Ampicillin is closely related to amoxicillin, another type of penicillin, and both are used to treat urinary tract infections, otitis media, uncomplicated community-acquired pneumonia, Haemophilus influenzae, salmonellosis and Listeria meningitis. It is used with flucloxacillin in the combination antibiotic co-fluampicil for empiric treatment of cellulitis; providing cover against Group A streptococcal infection whilst the flucloxacillin acts against the Staphylococcus aureus bacterium.

Use in research

Ampicillin is often used in molecular biology as a test for the uptake of genes (e.g., by plasmids) by bacteria (e.g., E. coli). A gene that is to be inserted into a bacterium is coupled to a gene coding for an ampicillin resistance (in E. coli, usually the bla gene, coding for β-lactamase). The treated bacteria are then grown on a medium containing ampicillin. Only the bacteria that successfully take up the desired genes become ampicillin resistant, and therefore contain the other desired gene as well.