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Objective:To establish a method for the determination of diisopropyl sulfate in ezetimibe. Methods:Diisopropyl sul-fate was determined by GC with a DB-FFAP capillary column (30 m × 0. 32 mm, 0. 5 μm) and an FID. The carrier gas was nitrogen and the flow rate was 2. 0 ml·min-1 . The temperature program was as follows: the initial column temperature was 40 ℃, and then raised to 180 ℃ at a rate of 25℃·min-1 ,and maintained for 2 min. Results:Diisopropyl sulfate had a good linear relationship with-in the range of 4. 040-13. 466 μg·ml-1(r=0. 999 8). The average recovery was 97. 57%and RSD was 2. 37% (n=9). Conclu-sion:The method is specific and reproducible with high sensitivity, which can be used to determine the content of diisopropyl sulfate in ezetimibe.
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Objective: To establish an HPLC method for the determination of luteolin-7-O-glucoside in Sedum Sarmentosum Bunge. Methods:The chromatographic column was Waters SymmetryShield C18(250 mm ×4.6 mm,5μm). The mobile phase consis-ted of tetrahydrofuran-methanol-water-phosphoric acid (9 ∶17 ∶74 ∶0. 25). The flow rate was 1. 0 ml·min-1. The detection wave-length was 350 nm. The chromatographic column temperature was 35℃. The injection volume was 10 μl. Results: The calibration curves were linear within the range of 5. 2-208. 0 μg · ml-1 ( r =0. 999 9 ) for luteolin-7-O-glucoside. The average recovery was 99. 12%(RSD=0. 94%,n=6). Conclusion:The method is simple, rapid, accurate, specific and repeatable. It can be used for the determination of luteolin-7-O-glucoside in Sedum Sarmentosum Bunge.
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Objective:To establish a headspace capillary GC method for the determination of residual solvents in bromfenac sodi-um. Methods:A headspace GC was used to separate the residual solvents on an HP-5 capillary column with an FID detector. The car-rier gas was nitrogen at the flow rate of 0. 8 ml·min-1 . The temperature of the injector was 200 ℃ and that of the FID was 250 ℃. The programmed column temperature was set as follows:maintained at 40℃ for 10 min, and then raised to 150℃ at the rate of 30℃·min-1 and maintained for 5 min. The containers of headspace injector were in equilibrium at 100 ℃ for 20 min. Dimethyl sulfoxide was used as the solvent. The amount of the residual solvents, such as methylbenzene, isopropanol, dichloromethane, methanol and iso-propyl ether was calculated by an external standard method. Results:All the solvents could be completely separated with good linear relationship. The average recovery of the five solvents was 98. 9%( RSD =2. 01%),99. 2% ( RSD =1. 95%),99. 6% ( RSD =1. 65%),100. 5%(RSD=1. 38%)and 100. 8%(RSD=1. 36%)(n=9),respectively. Conclusion:The method is simple and accu-rate in the determination of the five residual solvents in bromfenac sodium.
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Objective:To establish a method for the determination of trace nickel in agomelatine. Methods:An inductive coupled plasma atomic emission spectrometry method was applied in the determination at 221. 648 nm. The sample solution was prepared by the ignited residue of agomelatine. The content of nickel was determined using the standard curve. Results:The linear range was 0. 025-1. 000 μg·ml-1(r=0. 999 8). The RSD of precision was 0. 63%. The detection limit was 0. 000 8μg·ml-1. The quantitative limit was 0. 003μg·ml-1 . The average recovery was 99. 4% with RSD of 2. 20%. The RSD of repeatability was 1. 33%. Conclusion:The method is simple, sensitive and accurate in the determination of trace nickel in agomelatine.
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Objective:To establish a method for the determination of residual triethylamine in tenofovir disoproxil fumarate. Methods:The residual treithylamine was determined by GC with an Agilent DB-624 capillary column(30 m × 0. 53 mm,3 μm)and an FID detector. The carrier gas was nitrogen and the flow rate was 2. 0 ml · min-1 . The oven temperature was programming in-creased. The initial column temperature was 50℃,and then raised to 220℃ at a rate of 10℃·min-1 ,and maintained 4 min. Trieth-ylamine was quantified by an external standard. Results:The calibration showed a good linearity within the range of 53. 02-742. 34 μg ·ml-1 for triethylamine. The correlation coefficient was 0. 999 8. The recoveries were within the range of 96. 52%-102. 27%. The relative standard deviation(RSD)was 2. 42%(n=9). Conclusion:The method has good specificity,repeatability and sensitivity, which can be used in determining the content of residual trietbylamine in tenofovir disoproxil fumarate.
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Objective:To establish an HPLC method for the determination of levofloxacin in levofloxacin hydrochloride ophthalmic in situ gel. Methods:The chromatographic column was Agilent Zorbax C18(150 mm ×4.6 mm,5μm). The mobile phase consisted of hexane sulfonic acid sodium solution-methanol(72∶28). The flow rate was 1. 0 ml·min-1. The detection wavelength was 293 nm. The chromatographic column temperature was 40℃. The injection volume was 10 μl. Results:The calibration curve was linear within the range of 0. 040 3-0. 403 0 mg·ml-1(r=1. 000 0) for levofloxacin. The average recovery was 99. 8% (RSD=1. 08%,n=9). Conclusion:The method is accurate, simple and rapid, and suitable for the content determination of levofloxacin in levofloxacin hydro-chloride ophthalmic in situ gel.