EFFECT OF MAGNETICALLY CONTROLLED GASTRIC RESIDENCE OF SUSTAINED-RELEASE TABLETS ON BIOAVAILABILITY OF ACETAMINOPHEN

Two types of magnetically responsive sustained release tablets (magnetic tablet) with different drug release rates were prepared using acetaminophen (AAP) as the model drug. The effect of the gastric residence of these magnetic tablets on the bioavailability of AAP was investigated by magnetically controlling the gastric emptying time (GET) in beagle dogs. The area under the plasma concentration-time curve (AUG) of the AAP magnetic tablets after administration with magnet application increased about 2-fold as compared to that during administration without the application of the magnet. The mean residence time (MRT) of AAP magnetic tablets also tended to be prolonged by magnet application. It was suggested from the AAP absorption rate-time profiles obtained using a deconvolution method that the variation in these pharmacokinetic parameters was caused by the delay of 3 h in the GET. Furthermore, the variation in the pharmacokinetic parameters was influenced by the AAP release rate of the magnetic tablets.