TY - GEN
T1 - Modified alginate for biomedical applications
AU - Choudhary, Soumitra
AU - Reck, Jason
AU - Bhatia, Surita R.
PY - 2009
Y1 - 2009
N2 - Hydrophobically modified alginate (HMA) was synthesized by attaching n-octylamine groups on to the alginate backbone at low pH. At or above a critical concentration, HMA forms a physical gel in aqueous media due to hydrophobic interactions. Unreacted guluronic units of alginate were further crosslinked with divalent cations, such as Ca2+. Uniform gels were obtained by slow release of calcium ions from a calcium-ethylene diamine tetra acetic acid (Ca-EDTA) complex with the addition of D-glucono-δ-lactone (GDL). Mechanically stiffer gels of storage moduli ∼ 100 kPa were obtained at a relatively low polymer concentration of 2 wt% in the crosslinked gels. Solubility of a model lipophilic drug, sulindac, in HMA was found to be greatly improved compared to neat alginate, presumably due to preferential uptake of the drugs by micelles formed by the hydrophobic moiety. Extended release of sulindac was observed for upto 5-6 days, probably due to stronger crosslinked alginate units surrounding the hydrophobic rich domains. Small angle x-ray scattering data suggest a strong influence of hydrophobic group on the nanometer-scale structure, especially in the uncrosslinked state.
AB - Hydrophobically modified alginate (HMA) was synthesized by attaching n-octylamine groups on to the alginate backbone at low pH. At or above a critical concentration, HMA forms a physical gel in aqueous media due to hydrophobic interactions. Unreacted guluronic units of alginate were further crosslinked with divalent cations, such as Ca2+. Uniform gels were obtained by slow release of calcium ions from a calcium-ethylene diamine tetra acetic acid (Ca-EDTA) complex with the addition of D-glucono-δ-lactone (GDL). Mechanically stiffer gels of storage moduli ∼ 100 kPa were obtained at a relatively low polymer concentration of 2 wt% in the crosslinked gels. Solubility of a model lipophilic drug, sulindac, in HMA was found to be greatly improved compared to neat alginate, presumably due to preferential uptake of the drugs by micelles formed by the hydrophobic moiety. Extended release of sulindac was observed for upto 5-6 days, probably due to stronger crosslinked alginate units surrounding the hydrophobic rich domains. Small angle x-ray scattering data suggest a strong influence of hydrophobic group on the nanometer-scale structure, especially in the uncrosslinked state.
UR - https://www.scopus.com/pages/publications/72849118456
M3 - Conference contribution
AN - SCOPUS:72849118456
SN - 9781605111124
T3 - Materials Research Society Symposium Proceedings
SP - 137
EP - 141
BT - Advances in Material Design for Regenerative Medicine, Drug Delivery and Targeting/Imaging
T2 - MRS Fall Meeting 2008: Advances in Material Design for Regenerative Medicine, Drug Delivery and Targeting/Imaging
Y2 - 1 December 2008 through 3 December 2008
ER -