Formulation, physicochemical characterisation, and in vitro evaluation of quercetin-alginate microsphere system

Background: Quercetin exhibits various pharmacological properties. Unfortunately, quercetin has problems related to solubility, stability, and bioavailability, so it is necessary to develop an appropriate drug delivery system for quercetin. Objective: The study aims to develop a quercetin microsphere system and determine the effect of sodium alginate concentration on the physical characteristics and release of quercetin from the microspheres. Method: Quercetin-alginate microspheres were formed using sodium alginate with concentrations: Formula 1 (F1) 1%; Formula 2 (F2) 1.5%; Formula 3 (F3) 2% combined with 0.5 M CaCl2 using the ionotropic gelation and aerosolisation technique. Results: The study found that the higher alginate concentration significantly increased microsphere particle size (6.53 – 8.34 µm) and decreased drug loading (11.58% - 6.08%). In addition, too low or high alginate concentrations accelerated the quercetin release. Variations of alginate concentration did not significantly affect the encapsulation efficiency, polydispersity index, and moisture content properties. The kinetic release of the microsphere followed the Higuchi kinetics model with the diffusion-controlled mechanism. Conclusion: This study successfully developed an alginate microsphere system controlling quercetin release. In addition, variations in sodium alginate concentration affect the particle size, drug loading, and cumulative release of quercetin from the alginate microsphere system.