Analytical problems facing the development of electrochemical transducers for in vivo drug monitoring: an overview.

Even though significant progress has been made in the development of electrodes for the in vivo detection of catecholamines, oxygen, and various cations, there has been little research on the feasibility of continuously monitoring drugs in whole blood by electrochemical sensing devices. Electroanalytical problems associated with the development of such electrochemical transducers include the need for increased sensitivity and specificity, decreased biological matrix interferences, more rapid response times, improved miniaturization, and more reliable calibration procedures. We present a critical evaluation of potentiometric, conductometric, and amperometric techniques, with a brief review of basic principles and recent advances in ion-selective electrodes, chemical-sensing field-effect transistors, amperometric enzyme electrodes, and electrochemical immunosensors.