Chitosan‐based interpolymeric pH‐responsive hydrogels for in vitro drug release

Abstract

Two series of pH-responsive biodegradable interpolymeric (IPN) hydrogels based on chitosan (Ch) and poly(vinyl alcohol) (PVA) were prepared for controlled drug release investigations. The first series was chemically crosslinked with different concentrations of glutaraldehyde and the second was crosslinked upon g-irradiation by different doses. The equilibrium swelling characteristics were investigated for the gels at 378C in buffer solutions of pH 2.1 and 7.4 as simulated gastric and intestinal fluids, respectively. 5-Fluorouracil (FU) was entrapped in the hydrogels, as a model therapeutic agent, and the in vitro release profiles of the drug were established at 378C in pH 2.1 and 7.4. FTIR, SEM, and X-ray diffraction analyses were used to characterize and investigate the structural changes of the gels with the variation of the blend composition and crosslinker content before and after the drug loading.

Preparation of single or double-network chitosan/poly(vinyl alcohol) gel films through selectively cross-linking method

“…Those crosslinkers like borate (Miura, Kimura, Suzukia, Miyashita, & Nishio, 1999), tripolyphosphate (TPP) (Mi, Sung, Shyu, Su, & Peng, 2003) and glutaraldehyde (Schiffman & Schauer, 2007a, 2007b can form cross-linking structure with PVA and chitosan chain by non-covalent or covalent bonds. So far, applications of those cross-linked PVA/chitosan products in separation process, drug delivery and water treatment have been explored (Abdelaal, Abdel-Razik, Abdel-Bary, & El-Sherbiny, 2007;Ignatova, Starbova, Markova, Manolova, & Rashkova, 2006;Wang, Du, & Fan, 2005;Zhang, Mardyani, Chan, & Kumacheva, 2006). However, an organic integrity of the merits of those developed cross-linking techniques remains necessary not only for designing chitosan/PVA blend with controlled network structure, but for expanding their practical applications.…”

Biodegradable, pH‐Responsive Carboxymethyl Cellulose/Poly(Acrylic Acid) Hydrogels for Oral Insulin Delivery

“…Stimuli‐responsive materials have attracted increasing attention in recent years . Smart hydrogels undergo volume phase transitions or sol–gel phase transitions in response to external stimuli.…”

Stimuli-Responsive Polymers and Their Applications in Nanomedicine

“…Usually, the phase switches within 0.2-0.3 U of pH [46]. pH responsive polymers typically include chitosan [47], albumin [48], gelatin [49], poly(acrylic acid) (PAAc)/chitosan IPN [50], poly(methacrylic acid-g-ethylene glycol) [P(MAA-g-EG)] [51,52], poly(ethylene imine) (PEI) [53], poly(N,N-diakylamino ethylmethacrylates) (PDAAEMA), and poly(lysine) (PL) [54,55].…”