Alginate/chitosan particulate systems for sodium diclofenac release.

Alginate/chitosan particles were prepared by ionic gelation (Ca2+ and Al3+) for the sodium diclofenac release. The systems were characterized by electron microscopy and differential scanning calorimetry. The ability to release the active substance was examined as a function of some technological parameters and pH of dissolution medium. The release of sodium diclofenac is prevented at acidic pH, while is complete in a few minutes when pH is raised up to 6.4 and 7.2. The alginate/chitosan ratio and the nature of the gelifying cation allow a control of the release rate of the drug. The release mechanism was briefly discussed.