OBJECTIVE: To establish a UV method for the dissolution determination of voriconazole capsules and a simple and rapid LC-MS method for the determining the voriconazole concentration in human plasma after oral administration of self-manufacturing voriconazole capsule.The classical method of determining voriconazole was using ketoconazole as internal standard.While we have developed a novel method using Benzoyl metronidazole as internal standard can avoid the situation when patients combined using ketoconazole and voriconazole to expand the therapeutic effect would interfere with the accuracy of the result.Benzoyl metronidazole and voriconazole both have the same chemical constitution as azoles,which would be suitable for using as internal standard.METHOD: A UV method was developed for determing the dissolution of voriconazole capsules.According to the first method of appendix XC in Ch.P.2010, the determination condition was as follows: dissolution solution of 0.1 mol/L HC1 at (37±0.5) ℃, stirring speed of 100 r/min, detection wavelength of 256nm.In pharmacokinetic study ,blood samples were obtained following oral administration of 100mg voriconazole capsule at different time points.Liquid-liquid extraction was s used to extract voriconazole and Benzoyl metronidazole(IS).100μL of human plasma was extracted with acetonitrile after addition of 150ng/ml Benzoyl metronidazole (internal standard), and analyzed by Agilent 6460 Triple Quadrupole LC/MS system.Detection was operated under the multiple reactions monitoring (MRM) using electrospray ionization (ESI) and adding H ion mode.The precursor/product ion transitions of voriconazole and Benzoyl metronidazole (internal standard) were monitored at rn/z 350.13→281.2 and278.1.→ 149.1, respectively.The vcap capillary voltage was 4000V; drying gas temperature was 350 ℃; atomizing gas pressure 30psi; dry gas flow rate of 10L/min.The collision energy of voriconazole and Benzoyl metronidazole are 22eV and the decomposition voltage are 250eV.The recovery of voriconazole and IS was determined by comparing the responses of the analytes extracted from replicate QC samples (n =6) with the response of analytes from post-extracted plasma standard sample at equivalent concentrations.The stability of analytes and IS in the injection solvent was determined periodically by injecting replicate preparations of processed samples up to 18 h (in auto-sampler and room temperature) after the initial injection.Samples were considered to be stable if assay values were within the acceptable limits of accuracy (i.e., ±15% S.D.) and precision (i.e.,15% R.S.D.).In this study, the matrix effect was evaluated by analyzing QC sample.The effect of plasma constituents (matrix factor) over the ionization of analytes and IS was deter-mined by comparing the responses of the post-extracted plasma standard QC samples (n =6) with the response of analytes from neat samples at equivalent concentrations.RESULTS: The dissolution of voriconazole capsules 45 min was shown as 89.4%,(RSD 2.1%).In pharmacokinetic study ,the total run time was 2.0 min in positive mode and the elution of voriconazole and IS occurred at 1.608 min and 1.683 min, respectively; this was achieved with a mobile phase consisting of 0.1% (v/v) formic acid solution:acetonitrile (30∶70, v/v) at a flow rate of 0.20 mL/min on a HyPurity C18 (50 mm ×2.1 mm, 3.5μm) column.The calibration curve was linear in the concentration range of 31.25-2000 ng/ml(r>0.998).The lowest limit of quantification (LLOQ) reached 15.625ng/ml.A typical chromatogram for the control human plasma (free of analyte and IS) and human plasma spiked with voriconazole at LLOQ along with IS are compared, no interfering peaks from endogenous compounds are observed at the retention times of analytes and IS.The extraction recoveries were 95.22 %, 98.37 % and 98.05% for three QC concentration levels (31.25,250, 1000ng/ml) (n=6).The intra-and inter-day precision values for voriconazole met the acceptance as per SFDA guidelines.Voriconazole was stable in the stability studies, concluding the room temperature ,auto-sampler and freeze/thaw cycles stability.Average matrix factor values were 91.35%,101.67% and 101.87% for three QC concentration levels (31.25, 250, 1000ng/ml)(n=6).Matrix effect was not observed at analytes and IS retention times.Pharmacokinetic parameters of voriconazole after oral administration a single dose of capsule were as follow :Cmax was (6513.18±521.36) ng/ml, Tmax was (1.2±0.4) h, AUC0~24 was (42893.52±992.24) ng/ml, t1/2 was (67±2.3) h.CONCLUSION: The LC-MS/MS method proved to be sensitive, specific, simple and rapid, suitable for detection of the oral pharmacokinetic parameters of voriconazole capsule,which can be further used for blood concentration monitoring of.voriconazole capsule.