Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1223623 | Journal of Pharmaceutical and Biomedical Analysis | 2007 | 8 Pages |
Abstract
A method for the determination of lopinavir (LPV) concentrations in cerebral spinal fluid (CSF) and plasma ultrafiltrate (UF) was developed and validated to analyze clinical specimens from patients receiving antiretroviral treatment with lopinavir/ritonavir. The CSF (400 μL sample volume) final calibration range for LPV was 0.313-25.0 ng/mL. The final calibration range for UF (50 μL sample volume) was 1.25-100 ng/mL. The samples were prepared using liquid-liquid extraction, concentrated, and analyzed using a reversed phase isocratic separation. Detection was achieved in positive mixed reaction monitoring mode on a triple quadrupole mass spectrometer. Isolation of LPV through chromatographic separation and proper selection of calibration matrix were important factors in achieving accurate results. Plasma UF was found to be an equivalent calibration matrix to CSF whereas plasma matrix produced a positive bias in samples with unknown concentrations. Artificial CSF media prepared chemically were biased and less superior than UF. Sources of plasma for the UF did not affect accuracy. Several CSF sources were tested for specificity of the method and LPV concentrations were accurately produced with atmospheric pressure chemical ionization source producing more accurate results than the electrospray source. The method successfully measured LPV concentrations in CSF that were previously undetectable by HPLC as well as UF from protein binding studies.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Robin DiFrancesco, Robert DiCenzo, Glorimar Vicente, Julie Donnelly, Troy M. Martin, Luis A. Colon, Giovanni Schifito, Gene D. Morse,