Abstract

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