Alginate-Chitosan Particulate System for Sustained
Release of Nimodipine
Adhiyaman
Rajendran*1 and Sanat Kumar Basu2
1School
of Pharmacy and Health Sciences, International Medical
University, Kuala Lumpur, Malaysia, 2Division
of Pharmaceutics, Department of Pharmaceutical
Technology, Jadavpur University, Kolkata, India
*Corresponding author:
Email:
genomic2002@yahoo.com Tel: 0060-162702470
Received: 27 March
2009
Revised accepted: 20 July 2009
Tropical
Journal of Pharmaceutical Research, October 2009; 8(5):
433-440
Abstract
Purpose:
The
aim of this work was to prepare nimodipine-loaded
alginate-chitosan beads for sustained drug release.
Methods:
Nimodipine-loaded alginate-chitosan beads were prepared
by ionic gelation method using various combinations of
chitosan and Ca2+ as cations and alginate as
anion. The swelling ability and in vitro drug release
characteristics of the beads were studied at pH 1.2 and
6.8. Infra-red (IR) spectrometry, scanning electron
microscopy (SEM), differential scanning calorimetry
(DSC), x-ray diffraction (XRD), and atomic absorption
spectroscopy (AAS) were also applied to investigate the
physicochemical characteristics of the drug in bead
formulations.
Results:
The
surface morphology, size, and drug loading of the beads
varied with increase in the concentration of chitosan
and calcium chloride in the gelation medium. The
swelling ability of the beads in different pH media was
dependent on the presence of a polyelectrolyte complex
in the beads and the pH of the media. Both calcium
alginate beads and the beads treated with chitosan
failed to release the drug at pH 1.2 over the period of
study. On the other hand, at pH 6.8, calcium alginate
beads released approx. 96 % of drug in 6 h, but
treatment of the beads with chitosan lowered drug
release to 73 %. Drug release mechanism was either
“anomalous transport” or “case-II transport”. Data from
characterisation studies indicate that there was no
significant change in the physical state of the drug in
the bead formulations.
Conclusion:
Although nimodipine-loaded alginate beads showed poor
sustained release characteristics, modification with
chitosan yielded beads that exhibited sustained drug
release.
Keywords:
Alginate-chitosan beads; Nimodipine; Swelling;
Physicochemical characterization; Sustained release.
