Use of the InteliSite (R) capsule to study ranitidine absorption from various sites within the human intestinal tract

Purpose, The purpose of this study was to evaluate the extent of ranitidine absorption from an externally activated drug-delivery system in two distin ct regions of the intestine (jejunum and ileum) in healthy human volunteers . This investigation also was designed to evaluate the utility of the Intel iSite(R) capsule for studying regional intestinal drug absorption in humans . Methods, The intestinal absorption of ranitidine from the jejunum and ileum was compared in eight, healthy volunteers in this open-label, two-way cros sover study. In two of the eight volunteers, absorption from the colon also was studied. Subjects swallowed the capsule containing ranitidine solution (121 mg) and 100 mu Ci of Tc-99m-DTPA. The endcap of the capsule contained 20 mu Ci of In-111-DTPA. At the desired intestinal site; the capsule was a ctivated by the application of an external RF magnetic signal (6.78 MHz ope rating frequency) and the ranitidine solution was released. Blood samples w ere collected from a forearm vein for 12 hours after capsule activation. Results. The capsule released the ranitidine solution when activated in the jejunum, ileum and colon (visualized by the gamma camera). There was no di fference in the extent of ranitidine absorption or ranitidine pharmacokinet ics when the capsule was activated in the jejunum or ileum. Conclusions. This study demonstrates the utility of a novel, externally act ivated drug-delivery system to assess site-specific intestinal drug absorpt ion in humans. Results indicate that use of the InteliSite(R) capsule metho d to evaluate site-specific intestinal ranitidine absorption in humans yiel ds data similar to that obtained previously by means of oral intubation stu dies.