ABSTRACT
Amoxicillin–clavulanic acid is a combination product consisting of the semisynthetic antibiotic amoxicillin with the beta-lactamase-inhibitor clavulanic acid as a potassium salt. Clavulanic acid is a naturally occurring beta-lactamase inhibitor isolated from Streptomyces clavuligerus (Brown et al., 1976; Reading and Cole, 1977; see Chapter 13, Beta-Lactamase inhibitors). It contains a beta-lactam ring, and the sulfur of the penicillin thiazolidine ring is replaced with oxygen to form an oxazolidine ring (see Figure 14.1). Clavulanic acid has weak intrinsic beta-lactam activity, but its clinical utility relates to its potent inhibition of many beta-lactamases (Reading et al., 1983) and its ability to protect substrate drugs from hydrolysis (Bush, 1988). The molecular formula of clavulanic acid is C8H8KNO5. Chemically, clavulanate potassium is potassium –(2R,5R)-3-(2-hydroxyethylidine)-7-oxo-4-oxa-1-azabicyclo[3.2.0]-heptane-2-carboxylate and has a molecular weight of 237.25.
