Optimization of spray drying process conditions for producing insulin-loaded alginate/chitosan polyelectrolyte complexes

The aim of this study was to optimize the formulation parameters for spray-dried insulin-loaded alginate/chitosan polyelectrolyte complexes (PECs) intended for oral insulin delivery, utilizing response surface methodology. A 3-factor, 3-level Box-Behnken experimental design was used to assess the effects of three independent factors: alginate concentration, liquid feed rate, and inlet temperature, on three dependent responses: particle size, production yield, and entrapment efficiency. The structural properties and cytotoxic effects of insulin in the optimized spray-dried PECs were also investigated. The final optimized formulation achieved a particle size of 407.7 nm, a production yield of 58.88%, and an entrapment efficiency of 67.9%. In vitro release studies demonstrated that Alg/CS PECs exhibited pH-sensitive drug release behavior, following Makoid-Banakar kinetics. Structural analysis revealed that the spray-drying process maintained the native conformation and stability of the insulin. Moreover, the optimized formulations showed no cytotoxicity.