Study on swelling and drug releasing behaviors of ibuprofen-loaded bimetallic alginate aerogel beads with pH-responsive performance

Abstract

Bimetallic alginate aerogel beads were prepared by ionotropic gelation method with Ca²⁺-Ba²⁺ bimetallic solution and ibuprofen was loaded as a model drug. The swelling and drug releasing behaviors of the beads, especially the influence of barium, were investigated in artificial gastric and intestinal fluids. The results showed that these beads presented higher encapsulation efficiency due to the special structure of aerogel, and barium was beneficial for the more stable structure and drug releasing behavior. The lower swelling capacity of bimetallic beads was observed than monometallic beads. A rapid high-level releasing of ibuprofen was achieved in artificial intestinal fluid, which was up to 96.9% within 1 h, while ibuprofen releasing was avoided in artificial gastric fluid effectively. The drug releasing mechanism of these beads was explored in detail. In the bimetallic crosslinking system, Ba²⁺ presented a special effect on alginate beads with more sensitive pH response performance. Thus, these beads had more widely potential as a site-specific delivery system, especially for intestinal therapy.

Keywords: Aerogel; Alginate; Barium ion; Bimetallic; Drug releasing behavior; Swelling.