*For
correspondence:
E-mail:
shonary@mazums0ac.ir or
honary@yahoo.com
Tel: 0098 912 145 2220
Received: 1 June 2010
Revised accepted: 19
October 2010
Tropical
Journal of Pharmaceutical Research, December 2010;
9(6):
525-531
Abstract
Purpose:
To develop citrate crosslinked chitosan films using
chitosan of different molecular weights (MW) in order to
achieve site-specific delivery of a model non-polar
drug, indomethacin.
Methods:
Films prepared with different molecular weights of
chitosan and incorporating indomethacin as a non-polar
model drug were obtained by a casting/solvent
evaporation method. The chitosan films were crosslinked
by dipping in varying concentrations of sodium citrate
solution and for different crosslinking times. The films
were assessed by, amongst others, scanning electron
microscopy (SEM), dissolution studies and differential
scanning calorimetry (DSC) for surface morphology, drug
release and ingredient compatibility, respectively.
Results:
Crosslinking time and concentration of crosslinking
agent significantly (p < 0.05) influenced the in vitro
release of indomethacin as well as swelling of the
films. Also, the higher the molecular weight (MW) of
chitosan the lower the drug release rate (p < 0.05).
Furthermore, film swelling index rose as chitosan MW
decreased (p < 0.05). The practical absence of the sharp
endothermic peak characteristic of indomethacin in the
films suggests that crosslinking may have transformed
the drug from the crystalline to the amorphous state.
Conclusion:
The citrate-crosslinked chitosan films can be modulated
to vary swelling and drug release at pH 3.5 and 6.2;
this feature makes them useful tools for designing
site-specific delivery systems.
Keywords:
Chitosan film, Sodium citrate, Site-specific delivery,
Crosslinking, Indomethacin.
