Electrospray-assisted encapsulation of caffeine in alginate microhydrogels

One of the major challenges with microencapsulation and delivery of low molecular weight bioactive compoundsis their diffusional loss during storage and process conditions as well as under gastric conditions. In an attempt toslow down the release rate of core material, electrospray fabricated calcium alginate microhydrogels were coatedwith low molecular weight and high molecular weight chitosans. Caffeine as a hydrophilic model compound wasused due to its several advantages on human behavior especially increasing consciousness. Mathematical modelingof the caffeine release by fitting the data with Korsmeyer-Peppas model showed that Fick's diffusion lawcould be the prevalent mechanism of the release. Electrostatic interaction between alginate and chitosan (particularlyin the presence of 1% low molecular weight chitosan) provided an effective barrier against caffeine releaseand significantly reduced swelling of particles compared to control samples. The results of this study demonstratedthat calcium alginate microhydrogels coated by chitosan could be used for encapsulation of low molecularcompounds. However, more complementary research must be done in this field. In addition, electrospray, by producingmonodisperse particles, would be as an alternative method for fabrication of microparticles based on naturalpolymers.