Investigation of adsorption and release of diclofenac sodium by modified zeolites composites

Results on adsorption of diclofenac sodium (DS) by modified natural zeolite composites at three levels (10, 20 and 30 mmol/100 g) of cationic surfactant-hexadecyltrimethylammonium bromide (HB), in a buffer solution, were compared. Characterization of composites before and after drug adsorption was performed by determination of electrokinetic mobility, FTIR and thermal analysis. The results indicated interactions between drug and carriers. The pharmaceutical performance of cationic surfactant-modified zeolites as drug formulation excipients was evaluated by in vitro dissolution experiments. The results were compared with the drug release from corresponding physical mixtures. Prolonged drug release over a period of 8 h (up to 30%) was achieved with both groups of samples. Furthermore, DS release reached up to 85% from physical mixtures containing drug amount closer to a therapeutic dose.