Validation of Colchicine Assay Method for Therapeutic Drug Monitoring in Human Plasma

Abstract

Colchicine (C22H25NO6) reduces the frequency of attacks of Familial Mediterranean Fever (FMF) patients and is effective in preventing and arresting renal amyloidosis in most patients. Colchicine has narrow therapeutic window. The blood concentration to achieve therapeutic effects can be determined by running Therapeutic Drug Monitoring (TDM). However, the use of selective and sensitive analytical methods is necessary for achieving success with TDM. The purpose of this study is to develop and validate using Liquid Chromatograph- Tandem Mass Spectrometry (LC-MS/MS) to analyse quantitative assay of colchicine in human plasma samples for achieving a succesful TDM. In our study, to 1ml plasma sample, 0.25 ml internal standard solution was added. The solution was extracted by liquid-liquid extraction. The method was validated according to the EMEA. Total run time was 8 min in LC-MS/MS system. The method has been validated over the 0.25 - 8.0 ng/mL calibration range for colchicine. It was seen that the method has been validated since the results of the analysis meet the EMEA criteria. In our study colchicine plasma levels were found to be approximately 1.097±0.42ng/ml in FMF patients using an oral dose of 1.5-2 mg/day. A validated, rapid, simple, cost-effective and accurate LC-MS/MS method was developed and optimized for quantitation of colchicine in plasma. It is also a practical and easy method for pharmacokinetic studies involving the evaluation of TDM of colchicine.