Preparation and properties of konjac glucomannan/P(N-isopropylacrylamide-crotonic acid) hydrogel

A pH and temperature dual-responsive KGM/P(NIPAM-CA) hydrogel drug carrier was prepared by using natural polysaccharide konjac glucomannan (KGM), pH-sensitive monomer crotonic acid (CA), and temperature-sensitive monomer N-isopropylacrylamide (NIPAM). The effect of mass ratio of NIPAM to KGM on the properties of KGM/P(NIPAM-CA) hydrogels was studied by a range of testing methods. The drug loading and release properties of KGM/P(NIPAM-CA) hydrogel were investigated using 5-fluorouracil (5-FU) as a model drug. Results show that KGM/P(NIPAM-CA) exhibits good swelling and mechanical properties determined by its composition. As a drug carrier KGM/P(NIPAM-CA) hydrogel demonstrated a maximum encapsulation efficiency of 30.17% and a maximum drug loading capacity of 54.41% for 5-FU at 25°C. In simulated colonic fluid (SCF) at 25°C, the cumulative drug release rate of KGM/P(NIPAM-CA) reached 58.86% within 48 hours, which was 1.8 times higher than that in simulated gastric fluid (SGF). Furthermore, the hydrogel demonstrated biocompatibility, with a hemolysis rate of less than 3% and a cell viability exceeding 90%. These results establish KGM/P(NIPAM-CA) as a promising, biocompatible platform for stimuli-responsive, colon-targeted drug delivery.