A pH-responsive Artemisia vulgaris mucilage-co-acrylic acid hydrogel: Synthesis, characterization, controlled drug release, toxicity studies, and MRI

Abstract

Herein, the focus of this research is to develop a novel pH-responsive and non-toxic hydrogel via free radical polymerization of Artemisia vulgaris seed mucilage/hydrogel (AVH) and acrylic acid (AA) monomer using methylene-bis-acrylamide (MBA) as a cross-linking agent. The prepared copolymer hydrogel (AVH-co-AA) was characterized by FTIR and solid-state CP/MAS 13C NMR spectroscopic techniques. The thermal analysis revealed AVH-co-AA as a thermally stable material. The effect of pH and concentration of AVH, AA, and MBA on the dynamic and equilibrium swelling, sol-gel analysis, porosity measurement, drug loading, and in vitro drug release pattern of AVH-co-AA were evaluated. The maximum swelling of AVH-co-AA and the highest release of the drug (pantoprazole) was noticed at pH 7.4. The swelling indices (15.99 ± 1.1 to 26.07 ± 1.1 g/g at pH 7.4), porosity (33.41–56.03%), drug loading (103.4 ± 1.5 to 127.9 ± 2.2 mg/g), and drug release (66.6–98.2% after 24 h) were increased with increasing the concentration of AVH and AA, whereas all above parameters were decreased by increasing the concentration of MBA. The gel fraction decreased from 90.35 to 83.44% by increasing the concentration of AVH and increased from 87.23 to 90.43% and 85.60–89.75% by increasing the concentration of AA and MBA, respectively. The swelling of AVH-co-AA was also examined at pH 7.4 using MRI. The drug release followed zero-order kinetics and super case-II transport mechanism. Acute oral and dermal toxicity studies of AVH-co-AA did not exhibit any hematological, biochemical, or histopathological changes in the rat and rabbit models. Therefore, it can be concluded that AVH-co-AA is a pH-responsive and non-toxic polymeric material to develop sustained-release oral drug delivery systems.