Aceclofenac-loaded unsaturated esterified alginate/gellan gum microspheres: In vitro and in vivo assessment

Aceclofenac-loaded alginate/gellan gum microspheres for prolonged aceclofenac release were prepared through maleic anhydride-induced unsaturated esterification. The drug entrapment efficiency of these microspheres was found 39.30 ± 1.28% to 98.46 ± 0.40% and their average particle sizes were 270-490 μm. These microspheres were characterized by FTIR, DSC, P-XRD and SEM analysis. The in vitro dissolution indicated prolonged sustained release of aceclofenac over 6 h, which also followed the Korsmeyer-Peppas model (R2 = 0.9571-0.9952). The microspheres prepared through 3% (w/v) maleic anhydride-induced esterification exhibited comparatively slower drug-release. Most of the microspheres were followed Fickian diffusion mechanism except the microspheres containing higher gellan gum content, which followed anomalous (non-Fickian) diffusion. The in vivo results showed sustained systemic absorption of aceclofenac in rabbits and excellent anti-inflammatory activity in carrageenan-induced rats after oral administration over prolonged period.