Carbenicillin

Carbenicillin

Systematic (IUPAC) name
(2S,5R,6R)-6-{[carboxy(phenyl)acetyl]amino}- 3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0] heptane-2-carboxylic acid
Clinical data
Trade names	Geocillin
AHFS/Drugs.com	monograph
Pregnancy cat.	B (US) Passes into breast milk
Legal status	℞-only (US)
Routes	Oral, parenteral
Pharmacokinetic data
Bioavailability	30 to 40%
Protein binding	30 to 60%
Metabolism	Minimal
Half-life	1 hour
Excretion	Renal (30 to 40%)
Identifiers
CAS number	4697-36-3 Y
ATC code	J01CA03
PubChem	CID 20824
DrugBank	DB00578
ChemSpider	19599 Y
UNII	G42ZU72N5G Y
ChEBI	CHEBI:3393 Y
ChEMBL	CHEMBL1214 Y
Chemical data
Formula	C17H18N2O6S
Mol. mass	378.401 g/mol
SMILES O=C(O)[C@@H]2N3C(=O)[C@@H](NC(=O)C(c1ccccc1)C(=O)O)[C@H]3SC2(C)C
InChI InChI=1S/C17H18N2O6S/c1-17(2)11(16(24)25)19-13(21)10(14(19)26-17)18-12(20)9(15(22)23)8-6-4-3-5-7-8/h3-7,9-11,14H,1-2H3,(H,18,20)(H,22,23)(H,24,25)/t9?,10-,11+,14-/m1/s1 Y Key:FPPNZSSZRUTDAP-UWFZAAFLSA-N Y
Y (what is this?)  (verify)

Carbenicillin is a bacteriolytic antibiotic belonging to the carboxypenicillin subgroup of the penicillins. It was discovered by scientists at Beecham and marketed as Pyopen. It has Gram-negative coverage which includes Pseudomonas aeruginosa but limited Gram-positive coverage. The carboxypenicillins are susceptible to degradation by beta-lactamase enzymes, although they are more resistant than ampicillin to degradation. Carbenicillin is also more stable at lower pH than ampicillin.

Pharmacology

The antibiotic is very soluble in water and is acid-labile. A typical lab working concentration is 100 µg per ml.

It is a semi-synthetic analogue of the naturally occurring benzyl-penicillin. Carbenicillin at high doses can cause bleeding. Use of carbenicillin can cause hypokalemia by promoting potassium loss at the distal convoluted tubule of the kidney.

In molecular biology, carbenicillin may be preferred as a selecting agent (see Plasmid stabilisation technology) because its breakdown results in byproducts with a lower toxicity than analogous antibiotics like ampicillin. Carbenicillin is more stable than ampicillin and results in less satellite colonies on selection plates. However, in most situations this is not a significant problem so ampicillin is sometimes used due to its lower cost.

Additional reading

• Basker MJ, Comber KR, Sutherland R, Valler GH (1977). "Carfecillin: antibacterial activity in vitro and in vivo". Chemotherapy 23 (6): 424–35. doi:10.1159/000222012. PMID 21771. 

• Pawełczyk E, Zajac M, Knitter B, Mikołajczak P (October 1981). "Kinetics of drug decomposition. Part 66. Kinetics of the hydrolysis of carphecillin in aqueous solution". Polish journal of pharmacology and pharmacy 33 (3): 373–86. PMID 7322950.