Definition
ChEBI: A potassium salt having clavulanate as the counterion. It acts as a suicide inhibitor of bacterial beta-lactamase enzymes and has only weak anitbiotic activity when administered alone. However it can be used in combination with amoxicillin
trihydrate (under the trade name Augmentin) for treatment of a variety of bacterial infections, where it prevents antibiotic inactivation by microbial lactamases.
Manufacturing Process
Clavulanic acid may be obtained by aerobic cultivation of Streptomyces
clavuligerus in conventional nutrient media at, for example, about 25°-30°C
under roughly neutral conditions.
Cultivation of Streptomyces clavuligeru:
Streptomyces clavuligerus was cultivated at 26°C on agar slopes containing
1% Yeatex (yeast extract) ("Yeatex" is a Registered Trade mark), 1% glucose
and 2% Oxoid agar No. 3, pH 6.8. A sterile loop was used to transfer
mycelium and spores from the slope into 100 ml of a liquid medium in a 500
ml Ehrlenmeyer flask. The liquid medium had the following composition: Oxoid
Malt Extract 10g/L, Oxoid Bacteriological Peptone 10g/L, Glycerol 20 g/L, Tap
water 1 L.
The medium was adjusted to pH 7.0 with sodium hydroxide solution and 100
ml volumes dispensed into flasks which were closed with foam plugs prior to
autoclaving at 15 lb/sq.in. for 20 min. An inoculated seed flask was shaken for
3 days at 26°C on a rotary shaker with a 2 inch throw and a speed of 240
r.p.m.
Production stage flasks containing the liquid medium described above were
inoculated with 5% vegetative inoculum and grown under the same conditions
as the seed flask.
Clavulanic acid may be extracted from the culture medium. Normally the cells
of the Streptomyces clavuligerus are first removed from culture medium by
filtration or centrifugation. Then clavulanic acid is extracted into an organic
solvent, for example, n-butanol or ethyl acetate, or n-butyl acetate, or methyl
isobutyl ketone. Then n-butanol fraction are treated with new aqueous phase
using potassium hydrogen carbonate and then this aqueous phase is washed
with n-butanol. This aqueous extract, after separation of the phases, is
concentrated under reduced pressure. Freeze-drying at -20°C may also be
employed to provide a solid crude preparation of the potassium Z-(2R,5R)-3-
(β-hydroxyethylidene)-7-oxo-4-oxa-1-azabicyclo[3,2,0]heptane-2-carboxylate
(clavulanate potassium).
