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Aim TodevelopandvalidateaLC-MS/MS assay to quantify halometasone in rabbit plasma and study pharmacokinetics of halometasone after dermal topical administration of Halometasone Cream.Meth-ods Theplasmasamplewassubmittedtoliquid-liquid extraction using methyl tertiary butyl ether,with dexa-methasone as the internal standard (IS ).Chromato-graphic separations were performed on a Diamonsil C18 column(100 mm ×4. 6 mm,5 μm)with a linear gra-dient of methanol and 2 mmol · L-1 ammonium ace-tate.Halometasone and dexamethasone(IS)were ion-ized with an ESI source operated in negative ion mode, and the detected ions were m/z 503. 1→413. 0 (halo-metasone),m/z 391. 0→361. 0 (dexamethasone ). The test article could be monitored in rabbit plasma when following single dermal topical administration of Halometasone Cream at 1 g/100 cm2 to rabbits by u-singavalidatedLC-MS/MSassay.Results Calibra-tion curve was linear over the concentration range of0. 02~20 μg·L-1 in rabbit plasma.For low,medi-um,high concentration of QC solutions,the intra-and inter-day precision was in the range of 3. 72% ~7. 87%, and the accuracy was within 99. 1% to 103%. The pharmacokinetic parameters in rabbits were as follows:Tmax,Cmax,AUC0-t,T1/2 was (7. 38 ± 1. 06)h,(1. 16 ±0. 527)μg·L-1,(18. 8 ±7. 23)h·μg·L-1 ,(13. 8 ±3. 70)h,respectively.Conclusions ThisLC-MS/MSanalysismethodhashighsensitivi-ty,and sample processing method is simple,which has been rigorously validated.The method could be suc-cessfully applied to the pharmacokinetic study of halo-metasone after skin administration of Halometasone Cream to rabbits.
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Aim To develop a simple,rapid and ac-curate analysis method for determination of chiral ibu-profen in Beagle dog plasma.Method The plasma sample was submitted to liquid - liquid extraction u-sing hexane /isopropanol (95 ∶5,V/V),with ketopro-fen as the internal standard (IS).The separation was accomplished in a Lux 5u Cellulose-3 (250 mm·4.6 mm,5 μm)column,and the mobile phase consisted of methanol and a mixture of 1 mmol·L -1 ammonium acetate-methanol-formic acid (90 ∶1 0 ∶0.2,V/V/V) with the volume ratio of 82 ∶1 8 at a flow rate of 0.8 mL· min -1 .The mass spectrometer consisted of an ESI interface operating at negative ionization mode and the detection was performed using multiple reaction monitoring at the transitions of m /z 205.2 /1 61 .2 for ibuprofen and m /z 253.1 /209.2 for ketoprofen (IS). Method validation included the evaluation of the matrix effect, extraction recovery, linearity, lower LOQ, within-run and between-run precision,stability and di-lution effect.Results The calibration curve was line-ar across the concentration range of 0.2 ~50 mg·L -1 for each ibuprofen enantiomer with a lower LOQ of 0.2 mg·L -1 .The within-run and between-run precision (RSD%)was in the range 1 .01 % ~1 3.1 % for each ibuprofen.The pharmacokinetic parameters for orally single dose of (S +)and racemic ibuprofen in Beagle dogs were as follows: Cmax , T1 /2 , AUC(0-t) were (82.98 ±1 4.83 )mg·L -1 ,(3.21 7 ±0.7298)h, (362.0 ±58.67)h·mg·L -1 for (S +)ibuprofen and 70.62 /74.48 mg·L -1 ,1 .520 /5.432 h ,1 77.8 /649.6 h·mg·L -1 for (R -)/(S +)ibuprofen,re-spectively.Conclusions A simple,rapid,accurate, high sensitivity and repeatability method has been suc-cessfully developed,which can analyze the concentra-tions of (R -)/(S +)ibuprofen in Beagle dog plasma simultaneously.The method could be applied for the investigation of pharmacokinetics of ibuprofen enanti-omers in Beagle dogs.
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A rapid, sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of clevidipine butyrate and its primary metabolite clevidipine acid in dog blood. After one-step protein precipitation with methanol, the chromatographic separation was carried out on an Ecosil C18 column (150 mm x 4.6 mm, 5 µm) with a gradient mobile phase consisting of methanol and 5 mmol · L(-1) ammonium formate. A chromatographic total run time of 13.0 min was achieved. The quantitation analysis was performed using multiple reaction monitoring (MRM) at the specific ion transitions of m/z 454.1 [M-H]- --> m/z 234.1 for clevidipine butyrate, m/z 354.0 [M-H]- --> m/z 208.0 for clevidipine acid and m/z 256.1 [M-H]- --> m/z 227.1 for elofesalamide (internal standard, IS) in the negative ion mode with electrospray ionization (ESI) source. The linear calibration curves for clevidipine butyrate and clevidipine acid were obtained in the concentration ranges of 0.5-100 ng · mL and 1-200 ng · mL(-1), separately. The lower limit of quantification of clevidipine butyrate and clevidipine acid were 0.5 ng · mL(-1) and 1 ng · mL(-1). The intra and inter-assay precisions were all below 12.9%, the accuracies were all in standard ranges. Stability testing indicated that clevidipine butyrate and clevidipine acid in dog blood with the addition of denaturant methanol was stable under various processing and/or handling conditions. The validated method has been successfully applied to a pharmacokinetic study of clevidipine butyrate injection to 8 healthy Beagle dogs following intravenous infusion at a flow rate of 5 mg · h(-1) for 0.5 h.
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To explore the effects of Shenmai Injection (SMI), a compound traditional Chinese herbal medicine, on pharmacokinetics and serum concentration of digoxin when applied together with digoxin.
