Electrosprayed Soft Capsules of Millimeter Size for Specifically Delivering Fish Oil/Nutrients to the Stomach and Intestines

Contrasting to the traditional centimeter-sized soft capsules that are difficult to swallow or micro/nanometer-sized soft capsules that suffer from limited loading capacity for fish oil/nutrients and lowered stability, the millimeter-sized soft capsules with good enough stability could be a potential solution in solving these problems. Herein, we report millimeter-sized soft core shell capsules of 0.42-1.85 mm with an inner diameter of 0.36-1.75 mm, for fish oil/nutrients, obtained through an electrospray approach upon optimization of different fabrication parameters such as applied voltage, sodium alginate concentration, shell/core feeding rate ratio, times of feeding rate, and types of coaxial needles. Further in vitro and in vivo studies reveal that the resulting soft capsules were apparently weakened and became mechanically destructive in the simulated small intestine solution and were totally destroyed in the simulated small intestine solution if they were first treated in the simulated stomach solution but not in the simulated stomach solution, which makes the millimeter-sized capsules useful as containers for specific delivery of fish oils and lipophilic nutrients to the stomach and intestines with excellent in vivo bioavailability (>90%). The whole fabrication approach is very facile with no complicated polymer modification and formulations involved, which endows the resulting soft capsules with broad application prospect in food and drug industries.