•Preparation of pH sensitive succinyl chitosan/alginate core-shell nanoparticles.•Nanoparticles used diabetes treatment show 90nm size with −24mV zeta potential.•∼95% quercetin encapsulation with self-sustained release following non-fickian trend.•Pronounced hypoglycaemic effect and maintenance of glucose homeostasis in diabetics.•Safe, non-toxic, polymeric drug carriers for diabetes treatment. The study aims for development of an efficient polymeric carrier for evaluating pharmaceutical potentialities in modulating the drug profile of quercetin (QUE) in anti-diabetic research. Alginate and succinyl chitosan are focused in this investigation for encapsulating quercetin into core-shell nanoparticles through ionic cross linking. The FT-IR, XRD, NMR, SEM, TEM, drug entrapment and loading efficiency are commenced to examine the efficacy of the prepared nanoparticles in successful quercetin delivery. Obtained results showed the minimum particle size of ∼91.58nm and ∼95% quercetin encapsulation efficiently of the particles with significant pH sensitivity. Kinetics of drug release suggested self-sustained QUE release following the non-fickian trend. A pronounced hypoglycaemic effect and efficient maintenance of glucose homeostasis was evident in diabetic rat after peroral delivery of these quercetin nanoparticles in comparison to free oral quercetin. This suggests the fabrication of an efficient carrier of oral quercetin for diabetes treatment.