Evaluation of mucoadhesive coatings of chitosan and thiolated chitosan for the colonic delivery of microencapsulated probiotic bacteria

Abstract

Probiotic bacteria were previously encapsulated in sub-100 µm Ca(2+) alginate microcapsules for enhanced survival in human gastrointestinal tract. The aim of this study is to evaluate the altered mucoadhesive property of the probiotic delivery system by coating it with mucoadhesive chitosan or thiolated chitosan, for prolonged retention in human colon. The results confirmed that cross-linking with calcium ions reduced the mucoadhesive property of alginate hydrogel, thus questioning the intrinsic mucoadhesiveness of uncoated systems. In contrast, chitosan and thiolated chitosan were found to be adsorbed on sub-100 µm Ca(2+) alginate microcapsules, and substantially improved the mucoadhesion performance of the system. The adhesion performance was correlated to the amount of mucoadhesive coating polymer adsorbed on the surface of the system. The coated system was demonstrated on HT29-MTX colonic epithelial monolayer to deliver markedly higher amount of probiotic bacteria to the in vitro model of colonic mucosa. Additionally, the coatings were also found to exert significantly stronger mucoadhesion to colonic mucosa tissue at slight acid neutral pH with less ambient water, which conforms to the physiological environment of the colon, thus supporting prolonged retention in this region.

Thiolation of arabinoxylan and its application in the fabrication of controlled release mucoadhesive oral films

“…They have an effective role in the development of the stronger link to mucosal membrane, which is usually developed between thiol moiety and mucin proteins. In thiomers, immobilization of thiol moiety therefore enhances the mucoadhesive strength and mucoadhesion retention time of the thiolated polymer by 2–140-folds [7, 8]. Currently thiomers have comprehensive applications as an auspicious pharmaceutical excipient in the assessing era of pharmaceutical technology [9].…”

Hesperidin Hydrogel Formulation Using Pectin-Chitosan Polymer Combination

“…Through equations, it can be noted that the value of coefficient B (Chitosan) is greater than coefficient A (pectin), this indicates that Chitosan has a greater influence in increasing the mucoadhesive strength, compared to pectin. Cationic chitosan, when interacting with mucous glycoprotein which is anionic, sustains the electrostatic force, thereby increasing the strength of the mucoadhesive [36]. The results showed the formula with the highest concentration of chitosan (formula 2 and 4) has the highest mucoadhesive strength.…”

Introduction

“…Numerous studies on delivery of probiotic bacteria by means of their entrapment in polysaccharide gels were also carried out [20]. Recently, CHT and thiolated CHT were investigated with the purpose of appropriately modifying the mucoadesion properties of the gel [17], while laccase-crosslinked arabinoxylan was proposed because of its capability of being degraded by bacteria of the intestinal microbiota [89].…”

“…The major advantages of this route include accessibility, good blood supply, the ability to bypass first-pass liver metabolism, and permeability to large molecular weight drugs. Actually, formulations for vaginal drug release can be used, or have been proposed, for several clinical and potential usages [26]: as antivirus agents (e.g., HIV prevention [113]), contraceptives [92], antibacterial/antifungal agents [9,95], labour inducers [37], for hormone therapy as well as for vaccine and peptide/protein administration [110], and also against vaginal dryness [17], just to mention the most studied topics for practical utilization in this field. Together with suppositories, vaginal tablets and rings, gels and hydrogels have been also proposed for an appropriate vaginal distribution and retention of the dosage form, and polysaccharides were often employed for this purpose.…”