The resulting solution is then filtered to remove any undissolved acetylsalicylic acid and is mixed with a solution containing Cu2+ cations (copper(II) sulfate is suitable), precipitating bright blue crystals of copper aspirinate immediately. The crystals can then be filtered from solution, washed, and dried. An excess of acetylsalicylic acid is used in the first step, because it eliminates the possibility of unreacted carbonate anions precipitating the copper in this step.
4 NaC9H7O4 + 2 CuSO4 → C36H28Cu2O16↓ + 2 Na2SO4
Medicinal use
Copper aspirinate has been proven effective as a treatment for rheumatoid arthritis.[2] A pharmacokinetic study in healthy human volunteers supports its enhanced efficacy as compared with aspirin.[3]
The studies on animal models suggest that copper aspirinate is very promising in treating against thrombotic diseases and it has all the prospects of success in becoming an antithrombotic drug that prevents and treats thrombotic diseases in humans.[4]
Other uses
The use of copper aspirinate as a pigment in PVC and polystyrene has also been investigated.[5]
^MS Iqbal, M Sher, H Pervez & M Saeed (2008). "Pharmacokinetic Study of Copper (II) Acetylsalicylate" Biol. Trace Elem. Res. 124:283–288. doi:10.1007/s12011-008-8146-3
^Allan, J R; A Renton; W E Smith; D L Gerrard; J Birnie (1991). "A Study of the Performance of Bis(acetylsalicylate) Copper(II) and the Cobalt(II), Nickel(II) and Copper(II) Complexes of Pyridine-3,4-dicarboxylic Acid as Colouring Materials for Poly(vinyl chloride) and Polystyrene". Eur. Polym. J. 27 (7): 669–672. Bibcode:1991EurPJ..27..669A. doi:10.1016/0014-3057(91)90155-H.