Development of analytical methods for determination of drugs, used against tropical diseases, in biological fluids

Abstract: The overall aim of this thesis was to develop analytical methods for determination of drugs, used against tropical diseases, in biological fluids. For the treatment of malaria, piperaquine (PQ) is used in combination with another antimalarial. Human African trypanosomiasis is treated with eflornithine (DFMO), a chiral drug administered as a racemic mixture. A method for determination of PQ in capillary blood applied and dried onto sampling paper has been developed and validated. This method uses perchloric acid and acetonitrile to extract PQ from the biological matrix and sampling paper. The liquid phase is then loaded onto a strong cation-exchange solid-phase extraction column. PQ and the IS are separated on a Chromolith Performance column at high flow rate, allowing fast chromatography, and detected with UV absorbance detection. Capillary blood sampling onto sampling paper facilitates clinical studies performed in the field, eliminates need of venipuncture, simplify storage as well as transportation and makes handling samples safer for laboratory personnel. A method for determination of underivatized DFMO enantiomers in plasma has been developed and validated. Proteins are percipitated with trichloro acetic acid and the liquid phase is loaded onto a strong cation-exhange solid-phase extraction column. D-DFMO and L-DFMO and the IS are separated on a Chirobiotic TAG column with a chiral stationary phase. Detection is performed using evaporative light-scattering detection. This method allows study of behavior of individual enantiomers in humans. There is an indication that D-DFMO and L-DFMO differ and this needs to be investigated further. Therefore, a chiral method of determination is of value. This method has also been evaluated for determination of DFMO enantiomers in cerebrospinal-fluid.