Title
pH-responsive interpenetrating polymer network hydrogel microbeads of polyacrylamide-g-gum kondagogu and sodium alginate for gastroprotective drug delivery: in vitro-in vivo characterizations
Authors
GOPAL SALUNKHE, SOPAN NANGARE, PRATIKSHA DEVKAR, KETAN PATIL, PIYUSH BAFNA and LAXMIKANT ZAWAR

Received April 5, 2024
Published Volume 58 Issue 7-8 July-August
Keywords gum kondagogu, interpenetrating polymer network, pH responsive, microbeads, diclofenac sodium, anti inflammatory activity

Abstract
The present work aims to design interpenetrating polymer network (IPN) mediated hydrogel microbeads of hydrolyzed polyacrylamide-g-gum kondagogu (H-pAAm-g-GK) and sodium alginate (SA) for pH-sensitive gastroprotective drug delivery of diclofenac sodium (DS). In brief, the pAAm-g-GK was prepared using microwave irradiation, followed by conversion into a pH-sensitive polymer (H-pAAm-g-GK) using alkaline hydrolysis. Then, DS-loaded IPN microbeads were made utilizing an ionotropic gelation method using Ca+2 ions and glutaraldehyde (GA) as a crosslinking agent. After this, different characterizations, such as FT-IR, DSC, PXRD, swelling analysis, drug entrapment, drug release study, in vivo anti-inflammatory activity, etc., were performed. The amorphous state of DS in the microbeads was validated by thermograms and diffractograms, whereas SEM analysis confirmed the spherical shape of the obtained DS-loaded H-pAAm-g-GK@SA mediated microbeads. The pulsatile swelling analysis assured the H-pAAm-g GK@SA mediated microbeads showed significantly increased swelling as the pH switched from 1.2 to 7.4. Additionally, the microbeads exhibit a 15% DS release in a pH 1.2 buffer medium, while a substantial 94% of the drug was released in a pH 7.4 buffer. It assured the DS release was drastically augmented as the pH of the surrounding medium was switched from acidic to alkaline. Principally, the COOH- groups of hydrogels offer ionization at higher pH levels, wherein the osmotic pressure within the microbeads rises, resulting in more swelling and higher drug release. Finally, the in vivo anti-inflammatory activity assured pH-sensitive sustained release of DS. In conclusion, the H-pAAm-g-GK@SA mediated pH-sensitive IPN hydrogel microbeads show potential in the design of gastroprotective oral delivery systems for DS. In the future, H-pAAm-g-GK can be used for the design of pH-sensitive IPN hydrogel microbeads for targeted delivery.