Tailoring the composition of hydrogel particles for the controlled delivery of phytopharmaceuticals

Understanding the factors that control biopolymeric carriers' drug release profiles is essential to determine their applicability as drug delivery systems. We attempted to evaluate the relationships between the kinetics of the release of selected phytopharmaceuticals from a series of polysaccharide-based particles and the physicochemical properties of the resulting macro- and microcarriers, including alginate (ALG)- and carboxymethyl cellulose (CMC)-based particles with gelatine (GEL) or chitosan (CHIT) shells. Hydrogel beads (612-1080 mu m) and microparticles (8.5-44 mu m) were successfully loaded with esculin (ESC), hesperidin (HES), or thyme oil (TO), their morphology was elucidated by scanning electron microscopy (SEM), and the encapsulation efficiency was determined by spectrophotometry. The hydrogel carriers exhibited a prolonged payload release (similar to 90-300 min) under simulated gastrointestinal conditions, dependent on the coating type and pH environment. The variations in the particle composition influenced the drug release profiles, which were directly related to the carrier composition and payload characteristics. The Korsmeyer-Peppas and Peppas-Sahlin models, as well as a newly proposed hybrid model, provided the most appropriate description of the payload release from our particles when considered separately under the simulated gastric and intestinal conditions. Additionally, the Gallagher-Corrigan model was selected as the adequate one for predicting the consecutive payload release under those conditions. Establishing the most desirable mathematical model to predict the release profiles facilitated our comprehensively study the mechanism and release kinetics from multiple types of polysaccharide-based delivery vehicles loaded with phytopharmaceuticals possessing different structural and chemical features (i.e., water solubility and log P).