Report No xxxx - Instytut Fizyki JÄ drowej PAN

MICROTOMOGRAPHY STUDIES OF TABLETS
M. Zielińska, R. Marszałek, E. Sieradzki
Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1,
02-097 Warsaw, Poland
Magnetic resonance imaging (microtomography) is a unique method for studying
small objects. MRI has been widely used to monitor the diffusion of water into polymers. The
cellulose derivates, which form gel and swell on contact with water, were of special interest,
since these polymers are mainly used for controlled drug delivery[1,2].
Different behaviour on contact with water demonstrated copolymers of metacrylic
acids, such as Eudragit RL. It is water insoluble and has pH-independent permeability.
Therefore it is widely used in controlled release dosage forms which provide drug liberation
on entire gastrointestinal passage where different pH- values exist. MRI allows to monitor
water penetration into individual Eudragit RL matrix tablet.
The measurements were performed on a Bruker AVANCE 400 MHz NMR wide bore
spectrometer equipped with micro imaging probehead 20mm. The kinetic of water penetration
was followed using gradient echo fast imaging (mgefiortho) sequence with repetition time
100ms and echo time 2,5 ms.
[1]. Melia C.D., Rajabi-Siahboomi A.R., Bowtell R.W.: Pharm. Sci. Technol. Today 1, 32-39
(1998)
[2]. Bowtell R., Sharp J.C., Peters A., Mansfield P., Rajabi-Siahboomi A.R., Davies M.C.,
Melia C.D.: Magn. Reson. Imaging 12, 361-364 (1994)
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