Modifiable natural gum based microgel capsules as sustainable drug delivery systems.

Few hundred micrometer size microgel capsules from natural locust bean gum (LBG) was synthesized by means of divinyl sulfone (DVS) crosslinking in a surfactant free cyclohexane medium with 100% yield in 1 h. These LBG microgel capsules were chemically modified with different numbers of linear amine containing modifying agents such as ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetraamine (TETA) and branched polyethyleneimine (PEI) to induce cationic character for LBG microgels. The biggest change in zeta potential of LBG microgels that is +44.9 mV from -17.67 mV was observed upon the modification of LBG microgels with branched PEI (LBG/PEI). The blood compatibility studies were revealed that bare LBG microgels possess a good blood compatibility with non-hemolytic value, 0.96 ± 0.15%, and high blood clotting index, 87.35 ± 4.10%, whereas the blood compatibility of LBG/PEI microgels was found to be slightly-hemolytic, 4.96 ± 1.03%, and also moderate blood clotting index, 65.98 ± 98%. Additionally, sodium diclofenac (SDC) as a model drug was loaded into the LBG based microgels by directly loading from solution (absorption) and by chemical conjugation methods for in vitro release studies at physiological conditions, pH 7.4 at 37.5 °C A longer, and sustainable drug release profiles were obtained from chemical drug conjugated LBG microgels and the amine modified LBG microgels.