Enhanced intestinal stability and pH sensitive release of quercetin in GIT through gellan gum hydrogels

The objective of the work was to improve the intestinal stability and pH sensitive release of quercetin in the gastrointestinal tract. To achieve this aim, novel quercetin loaded pH sensitive hydrogel beads of gellan gum were developed through an ionic cross-linking technique using calcium chloride (CaCl₂) as cross-linking agents. Field emission scanning electron microscopy (FESEM) was used to characterize the morphological appearance of the prepared hydrogel beads. Drug-polymer and drug-CaCl₂ interaction were studied by using infrared spectroscopy. The important finding of the study was the formation of stable hydrogel beads at a very low concentration of CaCl₂ (0.3 % w/v). There was a drug polymer interaction in addition to polymer and CaCl₂ interaction that is confirmed by infrared spectroscopy. All the formulation shows good entrapment efficiencies within the range of 58.56-93.71 %. The prepared beads exhibited a pH responsive swelling behavior with maximum swelling at the simulated intestinal fluid (pH 7.4) (SIF). Hydrogel beads also showed a pH responsive release behavior and sustained release of drug at SIF. Moreover, the intestinal stability of quercetin was improved when encapsulated in gellan gum hydrogel beads in comparison to the solution containing quercetin.