Synthesis of Starch—Poly(Sodium Acrylate-co-Acrylamide) Superabsorbent Hydrogel with Salt and pH-Responsiveness Properties as a Drug Delivery System

Abstract

The synthesis and swelling behavior of a superabsorbent hydrogel based on starch (St) and polyacrylonitrile (PAN) were investigated. The physical mixture of St and PAN was hydrolyzed with NaOH solution to yield St—poly(sodium acrylate-co-acrylamide) superabsorbent hydrogels. The nitrile groups of PAN were completely converted to a mixture of hydrophilic carboxamide and carboxylate groups during the basic hydrolysis followed by in situ crosslinking of the PAN chains by the starch alkoxide ions. A mechanism for hydrogel formation was proposed and the structure of the product was established using FTIR spectroscopy. The effect of reaction variables, such as, base concentration, hydrolysis time, and temperature were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The optimized swelling capacity in distilled water was found to be >500g/g. The absorbency of the hydrogels indicated that the swelling ratios decreased with ionic strength increases. The St—poly(sodium acrylate-co-acrylamide) hydrogel exhibited a pH-responsive swelling—deswelling behavior at pH's 2 and 8. This on—off switching behavior provides the hydrogel with the potential to control delivery of bioactive agents. Release profiles of ibuprofen (IBU), a poor watersoluble drug, from the hydrogels were studied under both simulated gastric and intestinal pH conditions. The release was much quicker at pH 7.4 than at pH 1.2. The swelling rates of the hydrogels with various particle sizes were investigated as well.

Synthesis and characterization of a novel super-absorbent based on wheat straw

“…SAR is a new functional polymer material, which can absorb a large amount of water, where the weight can reach several hundred times its own weight and has excellent water retention even under some pressure. It has exhibited potential for application in many fields such as agriculture, hygienic products, waste-water treatment, drug-delivery and coal dewatering (Chu et al, 2006;Kamat and Malkani, 2003;Yi and Zhang, 2008;Sadeghi and Hosseinzadeh, 2008;Ende et al, 1995).…”

Preparation, characterization and properties of superabsorbent nanocomposites based on natural guar gum and modified rectorite

“…Superabsorbent can absorb and retain large amounts of aqueous fluids even under some pressure compared to general absorbents, so it has exhibited potential application in many fields such as agriculture (Chu, Zhu, Li, Huang, & Li, 2006;Puoci et al, 2008), hygienic products (Kamat & Malkani, 2003;Kosemund et al, 2009), wastewater treatment (Kas ßgöz, Durmus, & Kas ßgöz, 2008;Wang, Zhang, & Wang, 2008) and drug-delivery (Sadeghi & Hosseinzadeh, 2008). Thus far, many kinds of materials have been used for preparing superabsorbents, among them the naturally available resources such as polysaccharides and inorganic clay minerals have shown particular advantages and drawn considerable attention (Ray & Bousmina, 2005).…”

Hydrogels for the Application of Articular Cartilage Tissue Engineering: A Review of Hydrogels

“…e ibuprofen-release behavior of this hydrogel has been previously studied in a simulated intestinal and gastric pH environment [129].…”