Plasma protein binding and interaction studies with benoxaprofen

Pharmacology, clinical efficacy, and adverse effects of the nonsteroidal anti-inflammatory agent benoxaprofen

Benoxaprofen is a nonsteroidal anti-inflammatory agent that belongs to the arylalkanoic acid class of antirheumatic drugs. Animal studies have demonstrated that it has analgesic, antipyretic, and anti-inflammatory properties. Although benoxaprofen is a relatively weak inhibitor of cyclo-oxygenase in in vitro systems, inhibits lipoxygenase in other systems, and inhibits monocyte migration in some animal models of inflammation, it has not been established that it is unique with regard to these actions. Benoxaprofen undergoes hepatic metabolism via glucuronidation as the primary route of elimination and has a half-life of 28-35 hr. Clinical trials have demonstrated that its analgesic and anti-inflammatory properties are useful in the management of the signs and symptoms of rheumatoid arthritis and osteoarthritis. Once daily dosing of 300-600 mg is effective for many patients. In addition to gastrointestinal intolerance, photosensitivity and onycholysis are the most frequent adverse effects encountered. Recent reports of fatal cholestatic jaundice often associated with nephrotoxicity led to the withdrawal of benoxaprofen from world markets. It is uncertain whether it will once again be available for clinical use.

Plasma protein binding of zomepirac sodium

The plasma protein binding of zomepirac, a new nonnarcotic analgesic, was studied using equilibrium dialysis. Experiments were performed using human plasma and plasma from mice, rats, and rhesus monkeys, all species of pharmacological or toxicological interest. At concentrations approximating those achieved in vivo, the binding was fairly constant at 98-99% in all species except the rhesus monkey, where binding was decreased from 98 to approximately 96% at higher concentrations (greater then 50 microgram/ml). Zomepirac (10 microgram/ml) did not appear to displace or to be displaced by warfarin (10 microgram/ml) caused a concentration-dependent decrease in zomepirac (10 microgram/ml) binding. Zomepirac did not affect salicylate binding.