The purpose of this study is to determine pharmacokinetics of the probe-drugs sulfasalazine,
given in 240 ml non-caloric water and paracetamol, fexofenadine and valsartan after oral
administration, given in 240 ml non-caloric water, in 240 ml caloric drink or in 240 ml
grapefruit juice prior to ingestion and to visualize the localization and to measure the
filling volume of stomach, small intestine as well as ascending, transverse and descending
colon by T2-weighted magnetic resonance imaging after oral administration of 240 ml water
(non-caloric water), after administration of 240 ml caloric drink and after administration of
240 ml grapefruit juice.