RESUMEN
Objective: To establish a UPLC-MS/MS method for the determination of the residual quantity of potential genetoxic impurity 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) in ledipasvir.Methods: The chromatographic conditions were as follows: an Agilent ZORBAX SB-C18 (75 mm×4.6 mm, 3.5 μm) column was used with methanol-0.1% formic acid (50∶50) as the mobile phase.The flow rate was 0.3 ml·min-1.The column temperature was 30 ℃ and the injection volume was 5 μl.The mass spectrometry conditions were as follows: electrospray ionization source (ESI), multistage reaction monitoring (MRM), positive ion scanning mode, ion spray voltage of 2 500 V, ion source temperature of 500 ℃, atomization gas of 379.0 kPa, auxiliary gas of 275.6 kPa, curtain gas of 137.8 kPa, collision gas of 41.3 kPa, ion collision energy of 15 V and scan time of 100 ms.The MRM ion pair for quantitative analysis was m/z→156.2/86.1.Results: The linear range of EDC was 0.03-2.25 μg·ml-1 (r=0.999 0).The limit of detection was 0.03 ng and the limit of quantitation was 0.08 ng.The average recovery was 98.3%(RSD=5.7%, n=9).Conclusion: The method is simple, rapid and accurate, and can be used for the quality control of EDC in ledipasvir.
RESUMEN
Fluorescence spectroscopy was used to investigate the efficiency of coupling peptides to gold nanoparticles via 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride-N-hydroxysuccinimide (EDC-NHS).The experiment conditions including buffer solution, pH value and concentrations of buffer solution, concentrations of NHS and EDC, concentration ratios of NHS to EDC, and coupling reaction time on the coupling efficiency were investigated and optimized.The experimental results indicated that the optimized experimental conditions were as follows: 25 mmol/L HEPES buffer solution, pH 7.0;2∶1 of concentration ratio of NHS to EDC, 0.4 mol/L NHS, 0.2 mol/L EDC, and coupling reaction time of 24 h.This study may provide references for the relative research involving coupling peptide or protein with gold nanoparticles