caa a22 4500 477057047 CHVBK 20180405111349.0 cr unu---uuuuu 170330e19960501xx s 000 0 eng 10.1007/s002280050092 doi (NATIONALLICENCE)springer-10.1007/s002280050092 Investigation of nifedipine absorption in different regions of the human gastrointestinal (GI) tract after simultaneous administration of 13C- and 12C-nifedipine [Elektronische Daten] [H. Bode, E. Brendel, G. Ahr, U. Fuhr, S. Harder, A. H. Staib] Objective: To evaluate the absorption of nifedipine in man from four different sites of the gastrointestinal tract. Methods: On separate occasions, nifedipine solution was administered locally to the stomach, the small intestine and two sites in the colon in 4 healthy male volunteers (age 29-34 y weight 73-82 kg, non-smokers) using a remote controlled drug delivery device (HF-capsule). In order to assess absolute and relative bioavailabilities, an intravenous infusion was given on a separate occasion and all treatments were accompanied by a simultaneous oral dose of a stable-isotope labelled nifedipine solution. This allowed to minimise the influence of intra-individual variability. Plasma samples were collected up to 24 h post dose and faeces for 72 h. A new method of analysis of nifedipine in plasma and faeces using gas chromatography with mass-selective detection (GCMS) was employed. Results: Dissolved nifedipine was found to enter the systemic circulation completely along the intestine, being absorbed from jejunum to colon. Absorption was less rapid from the colon than from the upper part of the gut, but this was not associated with a decrease in absorption and/or bioavailability: Absolute bioavailability, calculated from the normalised AUC values, ranged from 42 to 56%, and bioavailability relative to oral solution was 100 to 126% (medians of the application sites). Conclusion: The absence of an absorption window in the intestinal tract suggests that nifedipine is well suited for use in controlled-release formulations. Springer-Verlag Berlin Heidelberg, 1996 Key words Nifedipine nationallicence GI absorption nationallicence HF-capsule nationallicence bioavailability nationallicence intra-individual variability nationallicence stable isotope labelled derivatives nationallicence Bode H. Institute of Pharmaceutical Technology, University of Bonn, Bonn, Germany, DE aut Brendel E. Institute of Clinical Pharmacology, Bayer AG, D-42096 Wuppertal, Germany, DE aut Ahr G. Institute of Clinical Pharmacology, Bayer AG, D-42096 Wuppertal, Germany, DE aut Fuhr U. Clinical Hospital, Department of Clinical Pharmacology, University of Frankfurt, Frankfurt/Main, Germany, DE aut Harder S. Clinical Hospital, Department of Clinical Pharmacology, University of Frankfurt, Frankfurt/Main, Germany, DE aut Staib A. H. Clinical Hospital, Department of Clinical Pharmacology, University of Frankfurt, Frankfurt/Main, Germany, DE aut https://doi.org/10.1007/s002280050092 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002280050092 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bode H. Institute of Pharmaceutical Technology, University of Bonn, Bonn, Germany, DE aut NATIONALLICENCE 700 1- Brendel E. Institute of Clinical Pharmacology, Bayer AG, D-42096 Wuppertal, Germany, DE aut NATIONALLICENCE 700 1- Ahr G. Institute of Clinical Pharmacology, Bayer AG, D-42096 Wuppertal, Germany, DE aut NATIONALLICENCE 700 1- Fuhr U. Clinical Hospital, Department of Clinical Pharmacology, University of Frankfurt, Frankfurt/Main, Germany, DE aut NATIONALLICENCE 700 1- Harder S. Clinical Hospital, Department of Clinical Pharmacology, University of Frankfurt, Frankfurt/Main, Germany, DE aut NATIONALLICENCE 700 1- Staib A. H. Clinical Hospital, Department of Clinical Pharmacology, University of Frankfurt, Frankfurt/Main, Germany, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer