Investigation of swelling and controlled drug kinetics of quaternary ammonium functionalized N-vinylimidazole-based copolymeric hydrogels

In this study, vinylimidazole based quaternary ammonium functional copolymer hydrogels were synthesized and their swelling behavior and drug release kinetics were investigated. For this purpose, N-vinylimidazole (VIm) and vinylbenzyltrimethylammonium chloride (VBTMAC) monomers were polymerized by free radical polymerization in the presence of azobisisobutyronitrile (AIBN) initiator and N,N-methylenebisacrylamide (BAAm) crosslinker. Swelling behavior of pVIm homopoymer and copolymeric hydrohgels containing %5, %10 and %15 VBTMAC copolymers (p(V-ko-Q5), p(V-ko-Q10) and p(V-ko-Q15), respectively) in water, depending on the amount of monomer and the pH of the environment; The release behavior of the model drug Naproxen Sodium salt (NS) was investigated by creating buffered gastric and intestinal environments. FTIR spectroscopy and SEM methods were used for the characterization of the synthesized homopolymer and copolymer hydrogels. The swelling behavior of hydrogels in water at different pH (3, 7, 11) was investigated. The p(VIm) homopolymer showed the highest swelling value of approximately 18 g solvent/g gel at pH 3, and the lowest Smax,d at pH=7 and pH=11 with a decrease of approximately 75%. In copolymers containing VBTMAC, on the other hand, p(V-co-Q15) copolymer showed the highest Smax,d value at pH 7. In this case, it is thought that the pH sensitivity decreases with increasing VBTMAC monomer ratio. While the amount of NS loaded on the p(VIm) homopolymer is 31.4 and 24.2 mg/g, the p(V-co-Q5), p(V-co-Q10), p(V-co-Q15) copolymers are 138.1 respectively. with 128.2: 222.4 with 225.5 and 292.5 with 305.8 mg/g. Considering the loaded NS amounts, the effect of the quantitative presence of the comonomer on the NS loading amount is in question. When the NS release characteristics are examined, the amount of drug-loaded and released for pH 2.6 (in the stomach environment) p(VIm) is low, reaching the highest release rate of 96.9%. The p(V-ko-Q5), p(V-ko-Q10), p(V-ko-Q15) copolymers reached a release rate of more than 90% at pH 7.4 (intestinal environment). It was observed that the gels synthesized in the NS release kinetic parameters made at pH 2.6 and pH 7.4 were compatible with the Higuchi and Korsmeyer-Peppas model and drug release followed more than one release mechanism. When the NS release was examined in pH 2.6 and pH 7.4 environments, it was seen that NS release was more controlled in pH 7.4 media.