DEVELOPMENT AND VALIDATION OF LC-MS/MS METHODS FOR THE SIMULTANEOUS QUANTIFICATION OF SOFOSBUVIR AND ITS MAJOR METABOLITE (GS-331007) IN BLOOD PLASMA, CEREBROSPINAL, AND SEMINAL FLUID: APPLICATION TO A PILOT CLINICAL TRIAL WITH A FOCUS ON ZIKA.

Zika still poses a threat to global health due to its association with serious neurological conditions and the absence of a vaccine and treatment. Sofosbuvir, an anti-hepatitis C drug, has shown anti-Zika effects in animal and cell models. Thus, this study aimed to develop and validate novel LC-MS/MS methods for the quantification of sofosbuvir and its major metabolite (GS-331007) in human plasma, cerebrospinal (CSF), and seminal fluid (SF) and apply the methods to a pilot clinical trial. The samples were prepared by liquid-liquid extraction and separated using isocratic mode on Gemini C 18 columns. Analytical detection was performed using a triple quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source. The validated ranges for sofosbuvir were 0.5 - 2000 ng/mL (plasma) and 0.5 - 100 ng/mL (CSF and SF), while for the metabolite they were 2.0 - 2000 ng/mL (plasma), 5.0 - 200 ng/mL (CSF), and 10 - 1500 ng/mL (SF). The intra-day and inter-day accuracy (90.8 to 113.8 %) and precision (1.4 to 14.8%) were within the acceptable values. The developed methods fulfilled all validation parameters concerning selectivity, matrix effect, carryover, linearity, dilution integrity, precision, accuracy, and stability, confirming their suitability for the analysis of clinical samples.