As with other non-selective NSAIDs, naproxen exerts it’s clinical effects by blocking COX-1 and COX-2 enzymes leading to decreased prostaglandin synthesis. Although both enzymes contribute to prostaglandin production, they have unique functional differences. The COX-1 enzymes is constitutively active and can be found in normal tissues such as the stomach lining, while the COX-2 enzyme is inducible and produces prostaglandins that mediate pain, fever and inflammation. The COX-2 enzyme mediates the desired antipyretic, analgesic and anti-inflammatory properties offered by Naproxen, while undesired adverse effects such as gastrointestinal upset and renal toxicities are linked to the COX-1 enzyme.

Clavulanic acid is a naturally derived beta lactamase inhibitor produced by Streptomyces clavuligerus. It has similar structure to beta lactam antibiotics which binds irreversibly to beta-lactamase enzymes and inactivates them. Clavulanic acid gives protection of Cefuroxime from degradation by beta lactamase enzymes and provides a solution for the treatment of bacterial infections caused by beta lactam resistant bacteria.

Capecitabine is a prodrug that is selectively tumour-activated to its cytotoxic moiety, fluorouracil, by thymidine phosphorylase, an enzyme found in higher concentrations in many tumours compared to normal tissues or plasma. Fluorouracil is further metabolized to two active metabolites, 5-fluoro-2′-deoxyuridine 5-monophosphate (FdUMP) and 5-fluorouridine triphosphate (FUTP), within normal and tumour cells. These metabolites cause cell injury by two different mechanisms. First, FdUMP and the folate cofactor, N^5-10 methylenetetrahydrofolate, bind to thymidylate synthase (TS) to form a covalently bound ternary complex. This binding inhibits the formation of thymidylate from 2-deoxyuridylate. Thymidylate is the necessary precursor of thymidine triphosphate, which is essential for the synthesis of DNA, therefore a deficiency of this compound can inhibit cell division. Secondly, nuclear transcriptional enzymes can mistakenly incorporate FUTP in place of uridine triphosphate (UTP) during the synthesis of RNA. This metabolic error can interfere with RNA processing and protein synthesis through the production of fraudulent RNA.