Development of luminescent techniques for the enhanced detection of immunosuppressants

Abstract

Immunosuppressants (ISs) are drugs used after an organ transplantation to prevent its rejection by inhibiting the body´s inmunological response. In transplanted patients, one of the most critical aspects is the correct dosage of ISs, which are characterized by narrow therapeutic window. At present, therapeutic drug monitoring (TDM) in post-transplanted patients is a standard practice and it consists in the measurement of the total drug plasma level measured just before the next dose by use of analytical techniques such as HPLC or LC-MS. However, recent clinical studies indicate that the free fraction (unbound to proteins) of ISs, which represents only 1-3% of the administered dose, reflects better the toxic or insufficient drug levels. Its clinical determination requires very low limits of detection. Alternative analytical methods such as fluorescence-based immunoassays (FIAs) are being developed for TDM. Some advantages of FIAs are their rapidity, low instrumental cost and high sensitivity.