Enhancing the Entrapment Efficiency of Alginate Floating Beads Using Double Emulsion Technique

Alginate beads intended to float in the stomach have several advantages over the traditional oral dosage forms. However, the formulation of these beads to deliver hydrophilic drugs such as captopril is a big challenge in terms of entrapment efficiency (EE) and extending the drug release. Here, we investigated the feasibility of using the double emulsion (DE) technique during the preparation of alginate floating beads to enhance the EE. This technique allows the incorporation of captopril into the oil droplets, the floating agent within the beads, which provides a hydrophobic barrier preventing drug loss.

Different DE beads were prepared using ionotropic gelation methods and compared with ordinary oil-entrapped beads based on the floating properties, EE, and drug release.

The results revealed that all the prepared beads have comparable floating properties, however, the EE was significantly increased from 11% for ordinary beads to 25% for DE beads. Moreover, the release of captopril from DE beads was markedly prolonged in comparison to that from ordinary beads. The SEM images clearly showed that the use of surfactant, tween 80, has a significant effect on the prepared beads through stabilizing the primary emulsion, maintain the drug dispersed within the oil droplets, and producing smooth beads with well-crosslinked surface and small well-dispersed oil droplets.

The findings of this study highlighted the potential of DE alginate beads as a promising drug delivery system, addressing the challenges associated with hydrophilic drug encapsulation.