Preparation of poly(acrylic acid)/linseed mucilage/chitosan hydrogel for ketorolac release

Abstract Studies of smart and biocompatible hydrogels have resulted in the development of efficient drug‐delivery systems controlled by external stimuli. Taking inadequate doses of ketorolac could cause health complications in humans. Therefore, it is necessary the development of a polymeric matrix for controlled drug delivery to extend the release of Ketorolac. In this work, acrylic acid was polymerized using ammonium persulfate as initiator and N , N ′‐methylenebisacrylamide as a cross‐linking agent, and in the presence of chitosan (Chit) and linseed mucilage (LS) biopolymers to obtain a composite of PAAc/LS/Chit hydrogel which was used for adsorption and release of ketorolac. Hydrogel was characterized by cryo‐scanning electron microscopy (Cryo‐SEM), Fourier transform infrared spectroscopy, and thermogravimetric analysis. The effects of pH on water hydrogel swelling percentage ( S ), water absorption percentage ( W ), and ketorolac‐releasing kinetics were studied. SEM analysis showed hydrogel pore size pH‐depending, with micropore diameters ranging between 5 and 10 nm at acidic pH, while for the hydrogel swollen at pH = 9, bigger pores are observed in the range of 30 to 50 nm. It was observed that S and W increased with the pH of the medium with an S of 608% at a pH of 9 following a Fickian behavior of water diffusion into the hydrogel pore and swelling kinetics represented by a second‐order model. Ketorolac kinetic release was well described through the Korsmeyer‐Peppas mathematical model, with the release rate increasing with the pH, extending the total release time of drug to 20 h.