Calcium Alginate and Calcium Alginate-Chitosan Beads Containing Celecoxib Solubilized in a Self-Emulsifying Phase

Abstract

In this work alginate and alginate-chitosan beads containing celecoxib solubilized into a self-emulsifying phase were developed in order to obtain a drug delivery system for oral administration, able to delay the drug release in acidic environment and to promote it in the intestinal compartment. The rationale of this work was linked to the desire to improve celecoxib therapeutic effectiveness reducing its gastric adverse effects and to favor its use in the prophylaxis of colon cancer and as adjuvant in the therapy of familial polyposis. The systems were prepared by ionotropic gelation using needles with different diameters (400 and 600 μm). Morphology, particle size, swelling behavior, and in vitro drug release performance of the beads in aqueous media with different pH were investigated. The experimental results demonstrated that the presence of chitosan in the formulation caused an increase of the mechanical resistance of the bead structure and, as a consequence, a limitation of the bead swelling ability and a decrease of the drug release rate at neutral pH. Alginate-chitosan beads could be a good tool to guarantee a celecoxib colon delivery.

Matrices (re)loaded: Durability, viability, and fermentative capacity of yeast encapsulated in beads of different composition during long‐term fed‐batch culture

“…78 Chitosan, a polycation, strengthens beads by forming a complex with alginate, which may protect crosslinking Ca 2+ from metal chelators. 63,71 Figure 1a-d indicates that the presence of chitosan significantly improved Young's modulus and viscosity for 7 days (Tables S1 and S2), consistent with previous studies noting increased durability with chitosan. 63,79…”

“…The resulting cell suspensions were successively diluted 1:10 seven times, and from each of these dilutions six 5 μl spots were plated on a YPD agar plate. 63,71 To estimate the mechanical and structural decline different matrices underwent as they aged, we calculated both the Young's modulus, 72 The gradual chelation of Ca 2+ ions, which are essential to the structural integrity of alginate gels, likely also contributed to the observed decrease in mechanical stability over time. impact the physical stress that beads can endure ( Figure S4).…”

“…Chitosan was added to two of four matrices as it has been previously shown to improve bead durability, perhaps by reducing calcium chelation. 63,71 To estimate the mechanical and structural decline different matrices underwent as they aged, we calculated both the Young's modulus, Table 2), which affects bead rigidity ( Figure S4). Based on these data, we expected that Pr beads would exhibit higher Young's modulus than NaAlg beads.…”

Physicochemical Properties of Glucomannan-Alginate as Vitamin C Excipient

“…As a result, the swelling of the matrix at pH 6.8 was higher than that at an acidic solution. Using a combination of alginate-chitosan excipient, Segale et al found higher swelling was also observed in pH intestinal [12]. Figure 1 also shows the effect of ratio glucomannanalginate on the swelling, in which the swelling was higher in the combined matrix than that of the lone glucomannan.…”

“…These sodiums could interact with the Ca 2+ of CaCl2 which linked to carboxylic groups of alginate during cross-link process. This replacement process of a bivalent ion with monovalent caused the breakup of the "egg-box" structure [12]. The egg box structure is described as the structure of calcium ions which bound in the periodic chelation sites located between two polyuronate chains [13].…”