Validation and clinical evaluation of an ultra-performance liquid chromatography with ultraviolet detector method for plasma quantification of micafungin.

Background: Factors associated with interindividual variability in the pharmacokinetics of micafungin have been identified. This variability can cause underexposure and loss of drug efficacy. For this reason, a simple, fast, cost-effective and sensitive ultra-performance liquid chromatography ultraviolet detector (UPLC-UV) method was developed and validated for the quantification of micafungin.

Methods: The method involves simple plasma precipitation by UPLC with a reversed phase C18 column at 40°C coupled with ultraviolet detection set at a wavelength of 264 nm. The mobile phase consisted of a mixture 42/58 of potassium phosphate 20 mm and acetonitrile.

Results: The method was validated over the concentration range of 0.25-15.0 mg/L and proved to be reliable and reproducible with an average percentage of recoveries of 101.59 ± 3.93% and inter and intraday variation coefficients lower than 15% in all cases. The method was successfully applied in determining 30 samples from 10 patients being treated with micafungin.

Conclusions: The method proposed could be useful to facilitate the implementation of therapeutic drug monitoring for personalizing micafungin treatment in invasive fungal infections.