Determination of amphotericin B in cerebrospinal fluid by solid-phase extraction and liquid chromatography

A highly sensitive and reproducible liquid chromatography (LC) method for the determination of Amphotericin B in cerebrospinal fluid has been developed and validated. This LC-based method involves using nystatin as an internal standard and solid-phase extraction for sample preparation, followed by reversed-phase separation monitored by absorbance at 410 nm. The method has a limit of quantification of less than 1 ng ml-1 and excellent precision and accuracy, with both percentage relative standard deviation and percentage relative error less than 10%. The established linearity range was 1-10 ng ml-1 (r2 > 0.99). The extraction recovery of Amphotericin B from the cerebrospinal fluid is higher than 90% over the entire linear range. The method has been successfully employed for studying the penetration of Amphotericin B into the central nervous system in dogs and human.