XAS applied to pharmaceuticals: drug administration and bioavailability

We present selected XAS applications, focused towards practical hospital qu estions of drug administration and bioavailability, where the technique is driven up to its limits of sensitivity. i) XAS was used to study the intera ctions between the components of parenteral nutrition solutions, in particu lar zinc and aminoacids, possibly modifying their bioavailability. ii) We s tudied by EXAFS a series of binary and ternary copperaminoacid complexes, i n view of the development of an efficient oral drug against copper deficien cies in Menkes disease. iii) EXAFS and XANES analysis allowed us to charact erise the solution form of a new arsenic containing drug against leukaemia. In parallel to the XAS measurements, we analysed trace elements levels alo ng patients' hairs, using X-ray fluorescence excited by synchrotron radiati on. The measurements along the hair allow for a monitoring of essential tra ce elements during therapy.