Sensing Methods of Immunosuppressant Drugs: Calcineurin Inhibitors and Purine Synthesis Inhibitor Agents

Abstract

Immunosuppression is associated as a necessary protocol in post-transplantation follow-up to improve graft survival rate. Two typical classes of immunosuppressants that have been commonly used as oral long-term medication are calcineurin inhibitors, e.g. cyclosporine A (CsA) and tacrolimus (TAC), and purine synthesis inhibitor agents, e.g. azathioprine (AZT) and mycophenolate (MF). As a common feature for all of them, they have a narrow therapeutic index which may lead to toxicity or effectiveness of therapy in super therapeutic and subtherapeutic concentrations, respectively. So, despite the undisputed value of immunosuppressants, therapeutic drug monitoring is a vital necessity for post-renal transplantation follow-up to maintain an appropriate balance between a predefined therapeutic dose and toxicity and likelihood adverse effects. Previously, most of the analytical methods that have been employed for immunosuppressant detection are based on immunoassay and chromatography methods which the drawbacks such as expensiveness, time-consuming responding, lack of stability, and skilled persons to interpretation obtained results make them inappropriate platforms for in-situ applications. In this way, we need facile, fast responding analytical methods as like optical and electrochemical sensors which can be developed to use in point-of-care applications. Here, we summarized the analytical methods for the determination of CsA, TAC, AZT, and MF which are based on fast responding methods.