Design and evaluation of oral delivery formulations based on dextran with theophylline

Manuel Efentakis, G. Atsidakos


The purpose of this investigation was to develop and evaluate different oral drug release delivery formulations namely, tablets and capsules, based on dextran, in order to determine how the quantity of dextran and the form-structure of the delivery systems influence drug release and release mechanisms. Theophylline was used as the model drug. All matrix tablets and one capsule formulation demonstrated sustained release profiles. The amount of dextran and its properties (particularly erosion) along with the form of the preparation were found to considerably affect the performance of the system, the release profiles and the mechanism of release. In all cases an increase in the quantity of dextran resulted in a decrease in the release rate indicating that acted as a kind of barrier and hindered the release of drug molecules from these formulations. Significant differences were also observed among the different preparations under examination, with the matrix tablets exhibiting the slowest drug release followed by the capsules.  By altering the dextran/theophylline ratio or the form of the preparation it is possible to obtain appropriate drug release. Consequently dextran appears to be a versatile material and a promising vehicle for the preparation of various oral sustained release drug delivery systems and relevant devices.



Dextran; theophylline; tablets; capsules; sustained release; release kinetics,

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