Adsorption-desorption process of Sodium Diclofenac in Poly-alkylcyanoacrylate nanoparticles.

The adsorption-desorption process of Sodium Diclofenac in nanosheres of Polybutylcyanoacrylate (PBCA) and Poly-isobutyl-cyanoacrylate (PIBCA) was studied. The adsorption efficiency was obtained according to the type of polymer (PBCA or PIBCA), the molecular weight and concentration of the stabilizers of the polymerization process (dextranes), and the pH of the adsorption medium. The adsorption increases by dextrane addition at the polymerization medium (maximum for the Dextrane 70) and decreases when the pH of the adsorption medium increases. The adsorption is better in PIBCA than in PBCA. A multilayer type BET's adsorption isotherm has been proposed. The desorption (release) of the drug, previously adsorbed in nanoparticles of PBCA and PIBCA with regards to the pH of de medium was also studied. The kinetics of drug release wa s asquare root of time diffusion process, depending on the polymer (higher in the PBCA), and the pH of the medium (decreases when the pH increases). A variable amount (15-40%) of the drug remains loaded to the nanoparticles. [ABSTRACT FROM AUTHOR]