A rapid and sensitive LC-MS/MS method for the quantification of fenofibric acid in rat plasma was developed and validated. Plasma samples were prepared by liquid-liquid extraction with a mixture of N-hexane-dichloromethane-isopropanol (100:50:5, v/v/v). Isocratic chromatographic separation was performed on a reversed-phase Discovery C(18) column (2.1 × 50 mm, 5 µm). The mobile phase was methanol-water-formic (75:25:0.25, v/v/v). Detection of fenofibric acid and the internal standard (IS) diclofenac acid was achieved by ESI MS/MS in the negative ion mode using m/z 317 → m/z 213 and m/z 294 → m/z 250 transitions, respectively. The method was linear from 0.005 to 1.250 µg/mL when 100 μL plasma was analyzed. The lower limit of quantification was 0.005 µg/mL. The intra- and inter-day precision values were below 8.2%, and accuracy ranged from -0.9 to 2.1% in all quality control samples. The recovery was 90.3-94.7% and 83.3% for fenofibric acid and IS, respectively. Total run time for each sample analysis was 2.5 min. The validated method was successfully applied to a pharmacokinetic study in six rats after oral administration of fenofibrate, the ester prodrug of fenofibric acid (equivalent to fenofibric acid 5 mg/kg). The method permits laboratory scientists with access to the appropriate instrumentation to perform rapid fenofibric acid determination.

Hole transport layer is of vital important for improving the photo-to-electron efficiency of perovskite solar cells. In this study, we investigate the performance of meso-structure perovskite solar cell applying bilayer materials for improving hole extraction ability. By simulating the performance of perovskite solar cell using wxAMPS software, CuOx is chosen to be ideal candidate of inorganic hole transport material which can moderate device property. The optimized value band offset in schematic diagram shows that photo-generated holes could be extracted from perovskite layer to spiro-OMeTAD efficiently by applying CuOx layer at the interface of perovskite/spiro-OMeTAD. Moreover, the experiment results show that Jsc of device increase to 19.5 mA/cm2, FF increase to 65.9% and total PCE reaches 12.3% by adopting CuOx/spiro-OMeTAD bilayer as hole transfer layer. Simultaneously, hysteresis decreases from 2% to 0.7% and integrated Jsc increase from 14.8 mA/cm2 to 16.03 mA/cm2. The PL results also confirm the mechanism of carrier extraction, which is consist with experimental results. It suggests that applying CuOx/spiro-OMeTAD bilayer is an efficient way to improve performance of perovskite solar cell.