ABSTRACT
Objective To develop and validate a LC-MS/MS method to quantify oxybutynin in rabbit plasma and evaluate the bioequivalence of self-prepared oxybutynin chloride gel and Gelnique. Methods The plasma sample was submitted to liquid-liquid extraction using methyl t-butyl ether after alkalified by 0.5 mol/L NaOH, with di-phenhydramine as the internal standard. Chromatographic separation was performed on a Kinetex C18column with the mobile phase consisting of 10 mmol/L ammonium acetate(1‰formic acid)-acetonitrile(50 : 50,v/v). Oxy-butynin and diphenhydramine were ionized with an ESI source operated in positive ion mode,and the detected ions were m/z 358→142 (oxybutynin),m/z 256→167(diphenhydramine). The validated method was then applied to the drug determination in rabbit plasma following single dermal topical administration of oxybutynin gel. Results Calibration curve was liner over the concentration range of 1~200 μg/L in rabbit plasma.For quality control samples, the intra-and inter-day precision was in the range of 1.67%~9.79%, and accuracy was within 92.9% to 103%. Self-prepared oxybutynin chloride gel and Gelnique were proved to be bioequivalent. Conclusions It was validated that the LC-MS/MS method is simple,strong specificity and high sensitivity,which could be successfully applied to pharmacokinetic study and bioequivalence evaluation of transdermal oxybutynin formulations in rabbit.
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ABSTRACT A rapid, sensitive, and accurate high performance liquid chromatography for the determination of Axitinib (AN) in rabbit plasma is developed using crizotinibe as an internal standard (IS). Axitinib is a tyrosine kinase inhibitor, used in the treatment of advanced kidney cancer, which works by slowing or stopping the growth of cancer cells. The chromatographic separation was performed on a Waters 2695, Kromosil (150 mm × 4.6 mm, 5 µm) column using a mobile phase containing buffer (pH 4.6) and acetonitrile in the ratio of 65:35 v/v with a flow rate of1 mL/min. The analyte and internal standard were extracted using liquid-liquid extraction with acetonitrile. The elution was detected by photo diode array detector at 320 nm.The total chromatographic runtime is 10.0 min with a retention time for Axitinib and IS of 5.685, and 3.606 min, respectively. The method was validated over a dynamic linear range of 0.002-0.2µg/mL for Axitinib with a correlation coefficient of r2 0.999.
Subject(s)
Rabbits , Chromatography, High Pressure Liquid/methods , Validation Study , Protein-Tyrosine Kinases/antagonists & inhibitors , Kidney Neoplasms/drug therapyABSTRACT
A sensitive, selective and high-throughput liquid chromatography–tandem mass spectrometry (LC–ESI–MS/MS) method was developed and validated for the quantitation of tolvaptan in rabbit plasma. Sample clean-up involved liquid–liquid extraction (LLE) and chromatography was performed on Zorbax SB C18 analytical column (50 mm ? 2.1 mm, 3.5 mm) using 0.1%formic acid:methanol (20:80, v/v) as the mobile phase. The parent-product ion transitions for the drug (m/z 449.2-252.1) and IS (m/z 456.2-259.2) were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) and positive ion mode. The method was validated over the concentration range of 0.10–1000.00 ng/mL and successfully applied to a pharmacokinetic study of healthy rabbits.
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Aim: A new, simple, rapid, very sensitive and accurate high performance thin-layer chromatographic (HPTLC) method has been developed and validated for estimation of Gemifloxacin in rabbit plasma. Study Design: Validation study. Methodology: HPTLC was performed on silica gel 60F254 plates with ethanol: ethyl acetate: hexane, 2:7:1 (v/v), as mobile phase. Densitometry scanning was performed in absorbance mode at λ=254 nm. Result: The RF value was 0.21. The response was a linear function of concentration over the range 0.1–0.7μg mL−1 (r2=0.996). A maximum recovery of drug from plasma was obtained by using chloroform and glacial acetic acid. Mean extraction recovery was 80%. Intra-day and inter-day precision (% RSD) of the assay were in the range 1.19–2.85% and accuracy was 1.7-5.66% Conclusion: This method can be applied to pharmacokinetic studies in rabbit plasma.
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Lamivudine has been widely used in the treatment of HIV disease. A reliable, sensitive reversed phase high performance liquid chromatography (RP-HPLC) method was developed and validated for lamivudine in rabbit plasma. The method was developed on Hypersil BDS C-18 column (250 mm × 4.6 mm, 5 μm) using a mobile phase of 0.25％ Triethylamine buffer (pH 3.0):acetonitrile (70:30, v/v). The efficient was monitored by UV detector at 256 nm. The total run time was 15 min with a flow rate of 1.0 mL/min. Calibration curve was linear over the concentration range of 25-2000 ng/mL. The retention times of lamivudine and internal standard (Nelfinavir) were 8.78 min and 10.86 min, respectively. The developed RP-HPLC method can be successfully applied for the quantitative pharmacokinetic parameters determination of lamivudine in rabbit model.
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AIM: To establish a sensitive and specific liquid chromatobraphy-mass spectrometry(time-of-flight)[LC-MS(TOF)] for the determination of astragaloside Ⅳ in rabbit plasma. METHODS: The HPLC-MS utilizing solid phase extraction was established to determine the concentration of astragaloside IV and ginsenoside R_~g1 , was used as internal standard. The analysis was carried on Agilent Hypersiol ODS(5 ?m, 4.6 mm?250 mm) column with a mobile phase of methanol-water (80∶20, v/v).Detection was performed on a time-of-flight mass spectrometry equipped with an ESI internal and operated in positive-ionization mode. Astragaloside Ⅳ quantitation was realized by computing the peak area ratio (astragaloside Ⅳ-ginsenoside R_~g1 )(astragaloside Ⅳ m/z807[M+Na]+ and ginsenoside R_~g1 m/z823[M+Na]+) and comparing them with calibration curve (r=~0.999 ). RESULTS: The linear calibration curve was obtained in the concentration range of 0.01-5 ?g?L~-1 .The detection limit of astragaloside Ⅳ was 0.01 ?g?L~-1 .The average recovery was more than 98%.The intra-and inter-run precision was measured to be below 5% of RSD. CONCLUSION: The method is sensitive, simple and rapid ,so, it can meet the need for the pharmacokinetics and bioavailability of astragaloside Ⅳ.