Title :
Hydrophobically modified alginate for drug delivery systems
Author :
Choudhary, S. ; Reck, J.M. ; Bhatia, S.R.
Author_Institution :
Univ. of Massachusetts, Amherst, MA
Abstract :
Hydrophobically modified alginate (HMA) was synthesized by an amide coupling reaction with alkyl amine (C8) at low pH. At and above a critical concentration, HMA forms reversible physical gel in aqueous media due to hydrophobic interactions. Unreacted guluronic units of alginate were further crosslinked with divalent cations, such as Ca2+, which resulted in a gel having elastic moduli ~100 kPa. Interplay of the two different gelation mechanisms, hydrophobic association and chemical crosslinking, enables us to tune the mechanical properties of the system. Solubility of a model lipophilic drug (Sulindac) was found to be improved at least by a factor of 5 compared to neat polymer, presumably due to preferential uptake of the drugs by micelles formed by hydrophobic moiety. Controlled and extended release of sulindac was observed for upto 5-6 days, probably due to stronger crosslinked alginate units surrounding the drug loaded hydrophobic rich domains.
Keywords :
association; biochemistry; drugs; elastic moduli; gels; hydrophobicity; polymers; Ca2+; alginate unreacted guluronic unit; alkyl amine; amide coupling reaction; aqueous medium; chemical crosslinking; divalent cation; drug delivery system; elastic moduli; gelation mechanism; hydrophobic association; hydrophobic interaction; hydrophobically modified alginate; lipophilic drug; mechanical property; polymer; reversible physical gel; sulindac; Bonding; Calcium; Chemicals; Drug delivery; Frequency; Mechanical factors; Polymers; Rheology; Stability; Viscosity;
Conference_Titel :
Bioengineering Conference, 2009 IEEE 35th Annual Northeast
Conference_Location :
Boston, MA
Print_ISBN :
978-1-4244-4362-8
Electronic_ISBN :
978-1-4244-4364-2
DOI :
10.1109/NEBC.2009.4967735
