Quantification of amikacin and kanamycin in serum using a simple and validated LC-MS/MS method

Background: Amikacin and kanamycin are frequently used in the treatment of multidrug-resistant TB. The current commercially available immunoassay is unable to analyze kanamycin and trough levels of amikacin. The objective was therefore to develop a LC-MS/MS method for the quantification of amikacin and kanamycin in human serum. Materials & methods: Using apramycin as internal standard, selectivity, accuracy, precision, recovery, matrix effects and stability were evaluated. Results: The presented LC-MS/MS method meets the recommendations of the US FDA with a low LLOQ of 250 ng/ml for amikacin and 100 ng/ml for kanamycin. No statistical significant difference was found between the LC-MS/MS method and the immunoassay of amikacin (Architect((R)) assay, p = 0.501). Conclusion: The low LLOQ of amikacin and the ability to analyze kanamycin makes the LC-MS/MS method the preferred method for analyzing these aminoglycosides.