Preparation and evaluation of a novel gastric floating alginate/poloxamer inner-porous beads using foam solution

In the present study, a simple and rapid method was developed to prepare a novel kind of inner-porous floating beads. The beads were prepared by dripping the foam solution into CaCl(2) solution using disposable syringe needle, where the foam solution consisting numerous of microbubbles with poloxamer 188 as foaming agents, alginate as foaming stablizer. Foamability and foam stability of different polymer ratios were evaluated. The SEM cross-section pictures of the beads showed that the beads were inner-porous and composed of bubbles with very thin wall bubbles stacked together. The visual observation result and the resultant-weight method confirmed that the floating beads showed good buoyancy, most beads could float in the stomach for more than 6 h. The floating beads release behavior in vitro showed that drug release from the beads in a sustained-release fashion for 10 h. Gamma scintigraphic images and pharmacokinetic studies in vivo showed that the beads can retained in the stomach for over 6 h and can improve the bioavailability of drug with narrow absorption window.