[Therapeutic monitoring of cyclosporine A]. / Terapeutické monitorování cyklosporinu A.

Cyclosporine A (CyA) is a drug with a specific influence on the immune system and it is used both to prevent tissue rejection of transplanted organs and to treat autoimmune diseases. The properties, metabolism, and methods of therapeutic drug monitoring (TDM) in patients under immunosuppressive therapy are described. TDM of CyA reflects the clinical condition of the patient during immunosuppression and may include pharmacokinetic and pharmacodynamic data obtained either from measuring CyA levels in blood, or from determining some other parameters, which are modulated by CyA (II-2). Although TDM is mainly based on analyzing trough levels of CyA, the determination of the whole biological exposition calculated as AUC enables better correlation with the clinical state of patients. Pharmacodynamic parameters have not been measured routinely yet.

[Determination of cyclosporine A using high-performance liquid chromatography]. / Stanovení cyklosporinu A metodou vysoce úcinné kapalinové chromatografie (HPLC).

Recent analytical possibilities of therapeutic drug monitoring (TDM) of cyclosporine A (CyA) both in solid organ transplanted patients and in patients with autoimmune diseases are described. The standard method for determination of CyA in blood is a validated HPLC method. HPLC methods were developed which make it possible to determine not only the parent drug, but also the main metabolites of CyA: AMI (M17), AM9 (M1), and AM4N (M21). Preparation of blood samples, their extractions and purifications are discussed. Chromatography is usually carried on C18 or CN columns by isocratic elution under high temperature (70 degrees C). CyD or CyC is used as the internal standard HPLC-MS method enables unambiguous identification of CyA metabolites after their separation on a chromatographic column and it is used mostly for research purposes only.

[Immunoanalytical methods of cyclosporine A determination]. / Imunoanalytické metody stanovení cyklosporinu A.

The standard method for determination of CyA in blood is a good validated HPLC method. HPLC methods were developed which make it possible to determine not only the parent drug, but also the main metabolites of CyA: AMI (M17), AM9 (M1), and AM4N (M21). HPLC methods for determination of CyA are very laborious and expensive. Most transplantation centres in the world use immunoanalytical methods for TDM of CyA. In recent years there has been an increase in the number of users of nonisotopic automated methods (Abbott TDx mono, AxSYM, Dade-Behring EMIT or Microgenic Cedia), which render instantaneous analysis possible. The analysis of the results of CyA in the blood in patients after transplantation shows that all immunoanalytical methods overestimate the concentration of CyA against HPLC results. The usually presented series of results is as follows: HPLC < RIA = EMIT < CEDIA < AxSYM < TDx. The differences are difficult to explain only by a different degree of cross reactivity for particular metabolites of CyA with the antibody used in the immunoanalytical method. The criterion of IFCC, which should be met by each immunoanalytical method in order to be used for TDM of CyA, should be redrawn, because it is not able to ensure sufficient specificity of the method. A suitable, cheap, and quick analytical method for TDM of CyA is still wanted. Some transplantation centres, including ours, carry out not only one method for effective TDM of CyA.