Anti-Inflammatory Activity of Curcumin-Loaded Chitosan Nanoparticles in a Carrageenan-Induced Paw Oedema Model

Abstract

Curcumin, the main pigment of turmeric, has a long record of anti-inflammatory activity in laboratory animals, but it is poorly absorbed and chemically unstable. Encapsulation in chitosan nanoparticles is widely proposed as a remedy, and the carrageenan-induced paw oedema model is the usual first test of whether the approach works. This narrative review asks how far that test can support the claim. It draws on published work on the model, on the pharmacology of curcumin and on chitosan-based carriers, and it reports no new data. The model is good at showing that swelling falls under controlled conditions and poor at explaining why. Much of the reported benefit of nanoformulation is better understood as improved handling, such as dispersion, stability and exposure, than as a new pharmacological action, and the apparent advantage depends heavily on the comparator used. Common weaknesses include comparison only with poorly soluble free curcumin, absent empty-particle controls, single time points, little measurement of tissue exposure and incomplete reporting of randomisation and blinding. The review concludes that a reduction in acute swelling is plausible, that its size and source are not established, and it lists what a decisive study would contain.