Moulded cross-linked chitosan matrix systems for controlled drug release

Abstract

Matrix-type drug delivery systems were prepared by moulding and drying cross-linked chitosan gels in 24-well plates and they were evaluated in terms of their physical properties, drug content, surface morphology and swelling. Furthermore, the in vitro drug release profiles were subjected to kinetic modelling at two different pH values. In general, the moulded matrix systems showed statistically significantly slower drug release compared to immediate release tablets as measured by the mean dissolution time. Drug release from the moulded matrix systems prepared from chitosan cross-linked with tripolyphosphate was pH-dependent as can be seen from the release exponent value (n) of 0.75 at pH 5.8 (anomalous transport, erosion), while the n value was only 0.40 at pH 7.4 (Fickian diffusion). The matrix systems obtained from chitosan cross-linked with sodium lauryl sulphate showed higher swelling but mostly Fickian diffusional release (n = 0.25 at pH 7.4, n = 0.41 at pH 5.8).

Keywords::

• Chitosan
• cross-linked gel
• controlled release
• matrix system
• sodium lauryl sulphate
• tripolyphosphate

Acknowledgements

We acknowledge the assistance of Dr Tiedt at North-West University, South Africa, with the Scanning Electron Microscopy studies.

Declaration of interest

Financial support from Tshwane University of Technology and the National Research Foundation is acknowledged. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.