Importance of pharmaceutical composition and evidence from clinical trials and pharmacological studies in determining effectiveness of chondroitin sulphate and other glycosaminoglycans: a critique

Abstract

Chondroitin sulphate (CS) has attracted much interest over the past two decades or so as a biological agent for use in the relief of pain and joint symptoms in osteoarthritis. Earlier clinical investigations produced variable, if encouraging results. This variability was partly due to limitations on the study designs and the lack of availability of standardized CS. Recently, high quality and fully standardized CS (Condrosulf) has become available and its effects have been studied in large-scale osteoarthritis trials, which are discussed here. There is now evidence for symptom- and structure-modifying (radiologically-observed) effects. These studies show that CS (a) has slow onset of response and that relief of pain may not be like that of the direct analgesic actions of non-steroidal anti-inflammatory drugs (NSAIDs), (b) there are indications of reduced need for intake of analgesics (e.g. NSAIDs) in patients taking CS, and (c) quality of life and cost-benefits may be associated with use of CS. Safety evaluations show that the incidence of adverse reactions is low. Pharmacokinetic studies indicate that although oral absorption is relatively fast CS has moderate oral bioavailability (15-24%) and that depolymerised and degraded CS that is evident after absorption, together with CS itself, may take some time to accumulate in target joints. The pharmacodynamic actions of CS indicate that it has anti-inflammatory effects that include multiple actions involving reduction of catabolic reactions and enhanced anabolic (proteoglycan) synthetic reactions in cartilage and may block osteoclast activation in bone. Further studies are required to (a) establish the effects of depolymerised and degraded CS on degradation of cartilage and bone in vitro, and (b) MRI and other investigations of the effects in osteoarthritis of long-term CS treatment. The findings from this review show there may be potential value of CS in reducing the dependence on intake of NSAIDs and analgesics in patients with osteoarthritis, while at the same time having favourable safety.