Synthesis and Characterization of Acrylamide/Acrylic Acid Co-Polymers and Glutaraldehyde Crosslinked pH-Sensitive Hydrogels

This project aims to synthesize and characterize the pH-sensitive controlled release of 5-fluorouracil (5-FU) loaded hydrogels (5-FULH) by polymerization of acrylamide (AM) and acrylic acid (AA) in the presence of glutaraldehyde (GA) as a crosslinker with ammonium persulphate as an initiator. The formulation’s code is named according to acrylamide (A1, A2, A3), acrylic acid (B1, B2, B3) and glutaraldehyde (C1, C2, C3). The optimized formulations were exposed to various physicochemical tests, namely swelling, diffusion, porosity, sol gel analysis, and attenuated total reflection-Fourier transform infrared (ATR-FTIR). These 5-FULH were subjected to kinetic models for drug release data. The 5-FU were shown to be soluble in distilled water and phosphate buffer media at pH 7.4, and sparingly soluble in an acidic media at pH 1.2. The ATR-FTIR data confirmed that the 5-FU have no interaction with other ingredients. The lowest dynamic (0.98 ± 0.04% to 1.90 ± 0.03%; 1.65 ± 0.01% to 6.88 ± 0.03%) and equilibrium swelling (1.85 ± 0.01% to 6.68 ± 0.03%; 10.12 ± 0.02% to 27.89 ± 0.03%) of formulations was observed at pH 1.2, whereas the higher dynamic (4.33 ± 0.04% to 10.21 ± 0.01%) and equilibrium swelling (22.25 ± 0.03% to 55.48 ± 0.04%) was recorded at pH 7.4. These findings clearly indicated that the synthesized 5-FULH have potential swelling characteristics in pH 6.8 that will enhance the drug’s release in the same pH medium. The porosity values of formulated 5-FULH range from 34% to 62% with different weight ratios of AM, AA, and GA. The gel fractions data showed variations ranging from 74 ± 0.4% (A1) to 94 ± 0.2% (B3). However, formulation A1 reported the highest 24 ± 0.1% and B3 the lowest 09 ± 0.3% sol fractions rate among the formulations. Around 20% drug release from the 5-FULH was found at 1 h in an acidic media (pH1.2), whereas >65% of drug release (pH7.4) was observed at around 25 h. These findings concluded that GA crosslinked 5-FU loaded AM and AA based hydrogels would be a potential pH-sensitive oral controlled colon drug delivery carrier.

IrO2/LiLa2IrO6 as a Robust Electrocatalyst for Oxygen Evolution Reaction in Acidic Media

Recently reported non-noble metal-iridium mixed oxides not only exhibit excellent activity for the oxygen evolution reaction in acid media, but also reduce the cost. However, most of them fail to...

Ultrafine Ruthenium-Iridium-Tellurium Nanotubes for Boosting Overall Water Splitting in Acidic Media

Design of high performance electrocatalysts is critical to electrocatalytic water splitting in acidic media. Herein, a replacement reaction with Te nanowires (NWs) is employed for the synthesis of ternary RuIrTe...

Investigation of enhanced electro-catalytic HER/OER performances of copper tungsten oxide@reduced graphene oxide nanocomposites in alkaline and acidic media

In this paper, we investigate electro-catalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of synthesized copper tungsten oxide@reduced graphene oxide (CuWO4@rGO) nanocomposites. The prepared CuWO4@rGO nanocomposites show bifunctional...

A Novel Indium-Induced-Synthesis In0.17Ru0.83O2 Nanoribbon as Highly Active Electrocatalysts for Oxygen Evolution in Acidic Media at High Current Densities above 400 mA cm−2

Ruthenium dioxide-based electrocatalyst possesses the most potential in acidic oxygen evolution reaction (OER), however, most of them show low current density, low mass activity and unsatisfied stability under strong acidic...