Gels from modified hydroxyethyl cellulose and ionic surfactants

Biocompatible and biodegradable pH-responsive hydrogels based on poly(acrylic acid) (AAc) and chitosan were prepared for controlled drug delivery. These interpolymeric hydrogels were synthesized by a gamma irradiation polymerization technique. The degree of gelation was over 96% and increased as the chitosan or acrylic acid content increased. The equilibrium swelling studies of hydrogels prepared in various conditions were carried out in an aqueous solution, and the pH sensitivity in the range of pH 1-12 was investigated. The AAc/chitosan hydrogels showed the highest water content when the 30 vol % AAc and 0.1 wt % chitosan were irradiated with a 30-kGy radiation dose. Also, an increase of swelling degree with an increase in the pH was noticed and showed the highest value at pH 12. The drug, 5-fluorouracil, was loaded into these hydrogels and the release studies were carried out in simulated gastric and intestinal fluids. The in vitro release profiles of the drugs showed that more than 90% of the loaded drugs were released in the first 1 h at the intestinal pH and the rest of the drug had been released slowly.

Section: Introductionmentioning

confidence: 99%

Preparation of poly(acrylic acid)–chitosan hydrogels by gamma irradiation and in vitro drug release

Shim

Nho

2003

“…Hoffmann et al investigated the effect of anionic surfactants such as sodium dodecylsulfate (SDS) and sodium tetradecylsulfate (STS) on the gelation of hydroxyethyl cellulose (HEC) and modified HEC samples with cationic groups (cat‐HEC) or with a cationic and hydrophobic group (cat‐HMHEC) 8. Kastner et al reported that on the addition of an oppositely charged surfactant, modified HEC solutions showed an associative phase separation at certain concentration of the surfactant followed by re‐solubilization with excess surfactant concentrations 9.…”

Section: Introductionmentioning

confidence: 99%

Influence of surfactant properties on thermal behavior and sol–gel transitions in surfactant‐HPMC mixtures

Joshi

Chen

2009

Four surfactants, namely, sodium n-decyl sulfate (SDeS), sodium n-hexadecyl sulfate (SHS), sodium n-dodecyl sulfate (SDS), and Triton X-100, were used as additives to study thermal behavior and sol-gel transformations in dilute aqueous hydroxypropyl methyl cellulose (HPMC)/surfactant mixtures using micro-differential scanning calorimetry. The influence of anionic surfactant, SDS on the gelation varied with SDS concentration where the sol-gel transition started at a higher temperature. Shape of the thermograms changed from single mode to dual mode at the SDS concentration of 6 mM and higher. SDeS and SHS, however, resulted in ''salt-in'' effect of a different magnitude during gelation. Triton X-100, being a non-ionic surfactant, showed a minor ''salt-out'' effect on the thermo-gelation process. On the basis of different thermal behavior of anionic and non-ionic surfactant/HPMC systems, a mechanism is proposed explaining how the chemical structure and electro-charge of the surfactants affect the polymer/surfactant binding and polymer/polymer aggregation because of hydrophobic interaction during the sol-gel transition.

“…Recent reports on chitosan/poly(acrylic acid) (PAAc) complexes deal with the work of thermal or photoinitiated polymerization and the blend method to obtain self‐curing chitosan/PAAc polymer complexes with an interpenetrating polymer network structure 9–11. However, radiation polymerization of AAc monomer in an aqueous chitosan solution has not been investigated.…”

Section: Introductionmentioning

confidence: 99%

γ‐Irradiation preparation of poly(acrylic acid)–chitosan hydrogels for in vitro drug release

Shim

Nho

2003

Biocompatible and biodegradable pH-responsive hydrogels based on poly(acrylic acid) and chitosan were prepared for controlled drug delivery. These interpolymeric hydrogels were synthesized by a ␥-irradiation polymerization technique. The degree of gelation was over 96% and increased as the chitosan or acrylic acid (AAc) content increased. The equilibrium swelling studies of hydrogels prepared under various conditions were carried out in an aqueous solution, and the pH sensitivity in a range of pH 1-12 was investigated. The AAc/chitosan hydrogels showed the highest water content when 30 vol % AAc and 0.1 wt % chitosan were irradiated with a 30 kGy dose of radiation. In addition, an increase of the degree of swelling with an increase in the pH was noticed and it had the highest value at pH 12. The drug 5-fluorouracil was loaded into these hydrogels and the release studies were carried out in simulated gastric and intestinal fluids. The in vitro release profiles of the drugs showed that more than 90% of the loaded drugs were released in the first 1 h at intestinal pH and the rest of the drug was released slowly.