Evaluation of Caffeine Release from Hydrogel Colloidosome under Simulated oral Condition and Instrumental Analysis of the Microcapsule

In this research hydrogel-based colloidosome with shell of CaCO3 microparticles was used in order to encapsulate caffeine as a model flavor compound. When the CaCO3 particles were dispersed in sunflower oil and then water in oil emulsion was prepared, with adding D-gluconic acid δ-lactone, water droplets containing alginate slowly gelate with outer layer of CaCO3 particles in micrometer hydrogels in the size of a few 10 µm without coagulation. CaCO3 microparticles act as both cross-linker for the alginate and stabilizer of water in oil emulsion. After leaving for 48 h, the hydrogel colloidosomes sank to the bottom of the container due to gravity. The results of infrared spectroscopy showed that indicative peaks of caffeine functional groups appeared in the loaded colloidosome sample spectrum and shifted its position. The results of calorimetric tests showed that the difference between the melting point of colloidosome samples with varying amounts of calcium carbonate microparticles in their formulas are linked. The results of the X-ray diffraction test showed a change in the crystalline degree of caffeine. After 5 h, the colloidosome sample, continued the caffeine release in water up to 55% maximally, while using mouth conditions for this sample, release of the loaded caffeine increased 33%. Generally, the results of instrumental analysis and release test showed that caffeine in the hydrogel colloidosome was well encapsulated within the alginate hydrogel network and have proper release under simulated oral condition.