Cross-linked high amylose starch is used as an excipient in
the preparation of pharmaceutical tablets for
the sustained release of drugs. NMR imaging wi
th contrast enhanced by proton density and by self-diffusion coefficient was used to follow
the water uptake and swelling, two critical parameters controlling
the drug release of
the cross-linked starch tablets containing 10 wt % of ciprofloxacin and of acetaminophen, respectively. The drug-loaded tablets were studied in a H
2O/D
2O mixture at 37 °C in comparison to
the tablets wi
thout any drug loading. The diffusion of water in
the tablets all showed a Fickian behavior, but
the kinetics of water uptake was faster in
the case of
the drug-loaded tablets. The formation of a membrane at
the water/tablet interface was observed.
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