Development of a novel pH sensitive silane crosslinked injectable hydrogel for controlled release of neomycin sulfate

Silane crosslinked biopolymer based novel pH-responsive hydrogels were fabricated by blending the cationic (chitosan) and anionic (alginate) polymers with poly(vinyl alcohol). Tetraethoxysilane (TEOS) was used, as a crosslinker in different amounts due to its nonhazardous nature, to study its impact on physical and chemical properties of the prepared injectable hydrogels along with the controlled release of drug. The swelling response of the prepared hydrogels was examined in different solvent media which exhibited decreased swelling ratio with increase in the amount of TEOS. All the fabricated hydrogels represented highest swelling at acidic pH while low swelling at basic and neutral pH. This specific pH sensitive behavior at pH 7 made them an appropriate candidate for the injectable controlled drug delivery in which Neomycin Sulfate (NMS) was successfully loaded on suitable hydrogel (comprising 50μL TEOS) to study its release mechanism. The results revealed that in simulated gastric fluid (SGF), hydrogel released the entire drug (NMS) in initial 30min while in simulated intestinal fluid (SIF), NMS was released in a controlled way up to 83% in 80min. These results endorsed that the hydrogels could be practiced as a smart intelligent material for injectable controlled drug delivery as well as for other biomedical applications at physiological pH.