Konjac glucomannan‐graft‐acrylic acid hydrogels containing azo crosslinker for colon‐specific delivery

Abstract

In this article, the synthesis and characterization of novel hydrogel systems designed for colon‐targeting drug delivery are reported. The gels were composed of konjac glucomannan, copolymerized with acrylic acid, and crosslinked by the aromatic azo agent bis(methacryloylamino)‐azobenzene. The influence of various parameters on the dynamic and equilibrium swelling ratios (SRs) of the hydrogels was investigated. It is shown that the SR was inversely proportional to the grafting degree of acrylic acid and the content of bis(methacryloylamino)‐azobenzene. The dependence of SR on the pH indicates that obtained hydrogels are potential for drug delivery to colon. It was possible to modulate the degree of swelling and the pH sensitivity of the gels by changing crosslinking density of the polymer. The main chain of hydrogels can be degraded by β‐glycosidase which is abundant in colon. They can be in vitro degraded for 73% in a month by Cereflo® and 86% in 20 days by Mannaway25L. We have also prepared the hydrogels that loaded with bovine serum albumin about 1.5%, 3%, 9%, and 20% by weight. In vitro release of model drug bovine serum albumin was studied in the presence of Mannaway25L or Fungamyl®800L in pH 7.4 phosphate buffer at 37 °C. The drug release can be controlled by the biodegradation of the hydrogels. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4370–4378, 2004

pH‐responsive semi‐interpenetrating networks hydrogels of poly(acrylic acid‐acrylamide‐methacrylate) and amylose. I. Synthesis and characterization

“…4,4 0 -Bis (methacryloylamino)azobenzene (BMAAB) was prepared according the method described earlier. 11 Yield ratio of BMAAB: 30%, mp 268-2698C, 1 …”

Dissolution of konjac glucomannan with room temperature ionic liquids

“…It is well known that there are large quantities of hydroxyl groups in KGM which can easily form KGM-water crystalline [29] . As for the TG curves of the raw KGM and regenerated KGM samples, there are different mass loss before the onset temperature, due to the loss of small amount crystal water.…”

Synthesis and characteristics of pH-sensitive semi-interpenetrating polymer network hydrogels based on konjac glucomannan and poly(aspartic acid) for in vitro drug delivery

“…It is mainly composed of a high-molecular weight glucomannan in which mannose and glucose units in a ratio of 1.6:1 are connected by b-(1,4) linkages (PéCrols et al,1997). Due to its biodegradability, biocompatibility, not degradable by digestive enzymes in upper gastrointestinal tract but degradable by b-mannanase (He, Zhang, & Huang, 2001) or other b-glycosidases abundant in colon, KGM shows promise in controlled release systems and serves as biomedical materials (Gonzalez et al, 2004;Liu, Hu, & Zhuo, 2004;Liu, Shao, & Lü, 2006;Wen, Cao, Yin, Wang, & Zhao, 2009).…”