Veronika Schreiber1, Marie Kitzmueller2, Martina Poxhofer2, Stefanie Gintersdorfer2, Catharina Neudorfer3, Maria Lichtneckert4, Christian Dittrich4, Martin Czejka5. 1. Department of Clinical Pharmacy and Diagnostics, University of Vienna, Vienna, Austria veronika.schreiber@univie.ac.at. 2. Department of Clinical Pharmacy and Diagnostics, University of Vienna, Vienna, Austria. 3. Department of Drug and Natural Product Synthesis, University of Vienna, Vienna, Austria. 4. Center for Social Medicine, Kaiser Franz-Josef Hospital with Gottfried von Preyer Pediatric Hospital, Hospital Pharmacy, Vienna, Austria. 5. Department of Clinical Pharmacy and Diagnostics, University of Vienna, Vienna, Austria Austrian Society of Applied Pharmacokinetics, Vienna, Austria.
Abstract
BACKGROUND: Drug monitoring is a useful tool for obtaining detailed information about the disposition of a drug in an individual patient during chemotherapy. According to the international guidelines, the analytical assay for quantification of a compound in biological samples must be validated. Among a number of parameters, peak purity is an important requirement. MATERIALS AND METHODS: We analyzed pharmacokinetics in patients who received chemotherapy with capecitabine and up to 10 various co-medications. RESULTS: Out of seven investigated co-administered drugs, we found evidence that the proton pump inhibitor pantoprazole causes peak interferences with capecitabine during high-performance liquid chromatography analysis. Therefore quantification of capecitabine in plasma samples can be inaccurate. CONCLUSION: We recommend an altered time schedule for co-administered drugs or changing the mobile phase used in the assay. Copyright
BACKGROUND: Drug monitoring is a useful tool for obtaining detailed information about the disposition of a drug in an individual patient during chemotherapy. According to the international guidelines, the analytical assay for quantification of a compound in biological samples must be validated. Among a number of parameters, peak purity is an important requirement. MATERIALS AND METHODS: We analyzed pharmacokinetics in patients who received chemotherapy with capecitabine and up to 10 various co-medications. RESULTS: Out of seven investigated co-administered drugs, we found evidence that the proton pump inhibitor pantoprazole causes peak interferences with capecitabine during high-performance liquid chromatography analysis. Therefore quantification of capecitabine in plasma samples can be inaccurate. CONCLUSION: We recommend an altered time schedule for co-administered drugs or changing the mobile phase used in the assay. Copyright