ABSTRACT
Personalized medicine is pushing forward new diagnostic techniques to aid in controlling drug therapeutic levels and their toxic effects. This study aims to develop a high-throughput screening method for therapeutic drug monitoring (TDM) and occupational exposure of cyclophosphamide (CP), an alkylating agent used as a chemotherapeutic and immunosuppressive drug. In order to achieve this goal, an immunizing hapten that exposes the cyclophosphamide moiety has been designed for the first time. Antibodies produced against this hapten have been used to develop an indirect competitive ELISA for the quantification of CP with high specificity and low cross-reactivity with some metabolites and other anticancer drugs. The assay obtained showed a LOD of 22 ± 6 nM in serum samples, with concentrations much below the blood CP levels of patients treated with the drug. A new tool for the detection and quantification of CP is provided which could be relevant for future pharmacokinetic studies and for therapeutic index improvement.
Subject(s)
Cyclophosphamide/blood , Animals , Antibodies/immunology , Cyclophosphamide/immunology , Drug Monitoring/methods , Enzyme-Linked Immunosorbent Assay/methods , Haptens/chemistry , Haptens/immunology , High-Throughput Screening Assays/methods , Humans , Immunoassay/methods , Limit of Detection , Phosphoramides/chemical synthesis , Phosphoramides/immunology , RabbitsABSTRACT
Cancer is a group of diseases in which abnormal cells grow and divide without control, with the potential to invade other parts of the body. Chemotherapy is a type of treatment that uses chemical agents to treat cancer. These drugs are toxic and produce undesirable adverse drug reactions due to their narrow therapeutic window and highly variable pharmacokinetics, thus, they need to be monitored to establish personalized treatment to achieve maximal efficiency and reduce drug toxicity. Nowadays, therapeutic drug monitoring (TDM) is not routinely used for chemotherapy agents, however, TDM has the potential to improve the clinical benefit of chemotherapy drugs. Tegafur, a prodrug of 5-fluorouracil (5FU), is one of the main anti-cancer drugs used worldwide. Herein, a reproducible and sensitive indirect competitive ELISA has been developed and validated in plasma samples. The assay reports an IC50 of 35.6 nM, reaching a limit of detection of 2.7 nM. It is highly reproducible and does not show cross-reactivity with any related compound. In summary, this assay provides a sensitive, accurate and high throughput analytical method for tegafur quantification in plasma, which fits TDM requirements.
