Development of biopolymer based matrix type multiple unit systems for sustained release of diclofenac sodium:: In vitro and in vivo evaluation

The objective of the present study was to investigate the applicability of matrix type chitosan treated alginate multiple unit systems (MUS) for sustained release of diclofenac sodium. The multiple unit systems (MUS) were prepared by the ionotropic gelation method. Spherical MUS with 1.852 +/- 0.041 - 2.173 +/- 0.265mm diameter range and 66.66 +/- 3.21 to 78.55 +/- 6.49% entrapment efficiency were produced. The addition of chitosan increased the swelling of MUS in acidic conditions and reduced the drug release from MUS. The fluoroscopic study reveals that the MUS retained in gastrointestinal tract (GIT) for more than 12 h and distributed throughout the GIT. The in vivo evaluation in healthy human volunteers of the MUS and that of Voveran SR tablets each containing 100 mg drug revealed that the MUS was bioequivalent to Voveran SR producing a non-significantly different (p>0.05) AUC. This study demonstrates that the matrix type chitosan treated alginate MUS can be a good alternative to sustained release tablets to deliver diclofenac sodium and expected to be less of an irritant to gastric and intestinal mucosa.