Preparation of alginate complex capsules containing eucalyptus essential oil and its controlled release

Abstract

Alginate complex capsules containing eucalyptus oil were prepared by the interfacial insolubilization reaction and its controlled release characteristics were examined. The capsule walls became substantially impermeable to eucalyptus oil by incubating the capsules at 37 °C for 20 min, when the preparation parameters were above the critical values of 1.0 w/v% sodium alginate, 2.0 w/v% calcium chloride and 20 min of the cross-linking time. The maximum oil content in the capsules was 90–92% at this condition. The time course of the oil release from the closed capsules was measured as a function of crashing force. It was confirmed that holding the capsules between fingers could control the oil release.