Designing of pH-Sensitive Hydrogels for Colon Targeted Drug Delivery; Characterization and In Vitro Evaluation

Abstract

In the current research work, pH-sensitive hydrogels were prepared via a free radical polymerization technique for the targeted delivery of 5-aminosalicylic acid to the colon. Various proportions of chitosan, β-Cyclodextrin, and acrylic acid were cross-linked by ethylene glycol dimethacrylate. Ammonium persulfate was employed as an initiator. The development of a new polymeric network and the successful encapsulation of the drug were confirmed by Fourier transform infrared spectroscopy. Thermogravimetric analysis indicated high thermal stability of the hydrogel compared to pure chitosan and β-Cyclodextrin. A rough and hard surface was revealed by scanning electron microscopy. Similarly, the crystallinity of the chitosan, β-Cyclodextrin, and fabricated hydrogel was evaluated using powder X-ray diffraction. The swelling and drug release studies were performed in both acidic and basic medium (pH 1.2 and 7.4, respectively) at 37 °C. High swelling and drug release was observed at pH 7.4 as compared to pH 1.2. The increased incorporation of chitosan, β-Cyclodextrin, and acrylic acid led to an increase in porosity, swelling, loading, drug release, and gel fraction of the hydrogel, whereas a decrease in sol fraction was observed. Thus, we can conclude from the results that a developed pH-sensitive network of hydrogel could be employed as a promising carrier for targeted drug delivery systems.

Release Rate Studies of 5-Aminosalacylic Acid Coated with Atomic Layer-Deposited Al2O3 and ZnO in an Acidic Environment

“…A first-order kinetics equation is regularly used to describe the release rates. 56 In our case, we find the use of eq 1 justified for the following reasons. First, our first-order kinetics modeling did not yield a high goodness of fit with the data, possibly attributed to a multimechanism for release which involves (i) mechanical action involving particle breakage exposing fresh surfaces and (ii) slow shell dissolution in the low pH solution.…”

“…A first-order kinetics equation is regularly used to describe the release rates . In our case, we find the use of eq justified for the following reasons.…”

Comparative study of the effect of cross‐linking degree on chitosan hydrogels synthesized with low and medium molecular weight chitosan

“…A sol fraction is the hydrogel's soluble portion, whereas a gel fraction is the hydrogel's insoluble component 34 . The sol contents of the hydrogels are shown in Table 1.…”

“…A sol fraction is the hydrogel's soluble portion, whereas a gel fraction is the hydrogel's insoluble component. 34 The sol contents of the hydrogels are shown in Table 1. In this study, the average sol contents of L-CS and M-CS hydrogels were calculated as 0.26 g/g and 0.44 g/g, respectively.…”

Biodegradable Gg-cl-poly(NIPAm-co-AA)/-o-MWCNT based hydrogel for combined drug delivery system of metformin and sodium diclofenac: in vitro studies

“…As the pH varied between 1.2, 7.4, and 9.2, deprotonation/ ionization of the polymer and monomer functional groups began, and hydrogel networks extended, causing swelling and drug release to rise. 43 Evidently, the copolymerization of NIPA with small amounts of AAc was extremely interesting since it provided a novel material that can modulate drug release according to medium pH, acquiring a potential utility for administration of oral matrix systems. As is well known, it is occasionally important to protect the gastric pH (pH = 1.2) from particularly labile medications, permitting their release once they have passed through the stomach and into the gastro intestinal tract, where the pH rises dramatically.…”