Colon‐specific oral delivery of vitamin B₂ from poly(acrylamide‐co‐maleic acid) hydrogels: An in vitro study

Abstract

Hydrogels, composed of poly(acrylamide-co-maleic acid) were synthesized and the release of vitamin B 2 from these gels was studied as a function of the pH of the external media, the initial amount of the drug loaded, and the crosslinking ratio in the polymer matrix. The gels containing 3.8 mg of the drug per gram gel exhibit almost zero-order release behavior in the external media of pH 7.4 over the time interval of more than their half-life period (t 1/2 ). The amount of the drug loaded into the hydrogel also affected the dynamic release of the encapsulated drug. As expected, the gels showed a complete swelling-dependent mechanism, which was further supported by the similar morphology of the swelling and release profiles of the drug-loaded sample. The hydrophilic nature of the drug riboflavin does not contribute toward the zero-order release dynamics of the hydrogel system. On the other hand, the swelling osmotic pressure developed between the gels and the external phase, due to loading of the drug by equilibration of the gels in the alkaline drug solution, plays an effective role in governing the swelling and release profiles. Finally, the minimum release of the drug in the swelling media of pH 2.0 and the maximum release with zero-order kinetics in the medium of pH 7.4 suggest that the proposed drug-delivery devices have a significant potential to be used as an oral drug-delivery system for colon-specific delivery along the gastrointestinal (GI) tract.

Breathing‐in/breathing‐out approach to preparing nanosilver‐loaded hydrogels: Highly efficient antibacterial nanocomposites

“…This is a common phenomenon and has been reported in a number of studies. 26 Fabrication and characterization of the hydrogelsilver-nanoparticle composites…”

Chemically treated hard gelatin capsules for colon‐targeted drug delivery: A novel approach

“…We also previously reported such zeroorder release from a loosely crosslinked matrix. 4,12 To sum up, it can be concluded that the chemically treated hard gelatin capsules (0.53% formaldehyde solution; treatment time 45 s) containing riboflavinloaded poly(N-viny1-2-pyrrolidone)-polyacrylamide cylindrical gel with crosslinking ratio 0.3 (in mol %) may prove to be an effective device for causing the desired delay in release of drug for colon-targeted delivery of protein and peptide drugs.…”

“…In our laboratory, we have synthesized a number of pH‐sensitive hydrogels and studied their drug‐release behavior 2–5. These devices are supposed to function on the generally accepted view that the pH of the human gastrointestinal tract increases progressively from the stomach (pH 2–3), to the small intestine (pH 6.5–7.0), to the colon (7.0–8.0) 6.…”

“…In our laboratory, we have synthesized a number of pH-sensitive hydrogels and studied their drug-release behavior. [2][3][4][5] These devices are supposed to function on the generally accepted view that the pH of the human gastrointestinal tract increases progressively from the stomach (pH 2-3), to the small intestine (pH 6.5-7.0), to the colon (7.0 -8.0). 6 Because these devices exhibit maximum swelling and release of the encapsulated drug in the pH range 7-8, they are supposed to bear the potential to be used for colon-targeted drug delivery.…”

Application of Taguchi Method to Investigate the Drug Release Behavior of Poly(Acrylamide‐co‐Maleic Acid)/Montmorillonite Nanocomposite Hydrogels

“…Synthetic polymers based on polyacrylamide (PAAm) have already been used as pH‐sensitive drug delivery systems . The polymers based on PAAm that have been copolymerized with a carboxylic acid monomer, such as maleic acid (MA) containing ionizable carboxylic groups, are anionic and pH sensitive .…”