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Objective:To provide basis for the rational use of valproic acid(VPA) in the patients with epilepsy through the analy-sis on the therapeutic monitoring data. Methods:The VPA plasma concentration and the other related information of 233 cases were analyzed retrospectively. Results:The total daily dose of VPA increased with age (P<0.05) in children group. Compared with that in adults group (19-50 years old),the target rate of VPA concentration was significantly higher in children group(4-14 years old) (P<0.001). VPA had similar antiepileptic effect in children and adults. Oral solution was the main dosage form for children and con-ventional tablets for adults. Children had higher target rate of VPA concentration than adults (P<0.05). Compared with the group with VPA alone,VPA combined with enzyme inducers such as carbamazepine,phenobarbital and phentoin significantly decreased the target rate of VPA concentration(P<0.001). Moreover,VPA combined with phenobarbital significantly decreased the total daily dose of VPA (P<0.05). Conclusion:With great inter-individual variance,VPA plasma concentration is associated with efficacy and side effects. Monitoring of VPA plasma concentration is useful to the individualized treatment of VPA.
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OBJECTIVE:To establish the method for the determination of tigecycline (TGC) in human plasma. METHODS:After precipitated by acetonitrile,the plasma sample was determined by LC-MS/MS. Using d9-TGC as internal standard,Kromasil C18 column was used with mobile phase consisted of water (containing 0.05% TFA)-acetonitrile (gradient elution) at flow rate of 0.6 ml/min,column temperature of 40 ℃. The ion transitions were performed under ESI positive MRM model at m/z 586.3→513.2 and m/z 595.3→514.3 for TGC and internal standard,respectively. RESULTS:The linear range of TGC was 25-2 000 ng/ml (r=0.999 8),and lowest quantification limit was 25 ng/ml;intra-day and inter-day RSD was 3.15%-7.23%,and relative error was-4.53%-10.48%. Plasma sample kept stable after 3 times of freezing and thawing cycle,at room temperature for 24 h,in automat-ic sample injector for 24 h and freezing for 42 d (RSD<15%). Plasma concentration of TGC was 0-438.0 ng/ml in one patient with pan-drug resistant bacteria infection(0-12 h after administration). CONCLUSIONS:The developed method is accurate,sensi-tive and specific,and can be used for plasma concentration determination of TGC and pharmacokinetic study.
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OBJECTIVE:To establish and validate the method for the determination of carbamazepine (CBZ) in human plas-ma,and to apply the method for external quality assessment. METHODS:After precipitated with acetonitrile,the plasma sample was determined by LC-MS/MS. Using loratadine as internal standard,the determination was performed on Kromasil C18 column with mobile phase consisted of water (containing 0.1% formic acid)-acetonitrile (gradient elution) at flow rate of 0.6 ml/min and column temperature of 40 ℃. The ion transitions under MRM mode by ESI+ ionization were performed at m/z 237.1→194.0 and m/z 383.1→267.0 for CBZ and internal standard,respectively. RESULTS:The linear range of CBZ were 5-1 000 ng/ml (r>0.998). The limit of quantitation was 5 ng/ml. RSDs of inter-day and intra-day were 1.00%-6.42%;relative deviation were -6.93%-0.32%. The external quality assessment of 5 samples were 679.0,475.0,104.0,29.2 and 26.2 ng/ml,respectively. The pass rate of assess-ment result was 100%. CONCLUSIONS:The method is sensitive,accurate and specific. The method is applicable for the plasma concentration determination and external quality assessment of CBZ.
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Objective:To evaluate the uncertainty in carbamazepine ( CBZ) determination in human plasma by HPLC-MS/MS. Methods:The whole process of CBZ determination was analyzed and the uncertainty sources were established, and then the uncertainty was evaluated and combined, and the expanded uncertainty was also calculated. Results: The expanded uncertainty of CBZ with low (7.46 ng·ml-1) and high (745 ng·ml-1) levels was 0.410 ng·ml-1 and 33.400 ng·ml-1, respectively (P=95%, k=2). Conclusion:The uncertainty in CBZ determination in human plasma by HPLC-MS/MS is mainly caused by recovery, sample prepara-tion and matrix effect for low concentration, and by sample preparation and repeatability for high concentration.
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Objective:To evaluate the uncertainty in the determination of lamotrigine(LTG)in human plasma by LC-MS/ MS. Methods:The uncertainty sources in the determination of LTG were analyzed and the uncertainty was evaluated and combined. Re-sults:The expanded uncertainty of LTG at low(0. 050 4 μg· ml - 1 )and high(1. 27 μg· ml - 1 )concentrations was 0. 005 18 μg· ml - 1 and 0. 066 4 μg· ml - 1 ,respectively(P = 95% ,k = 2). Conclusion:The uncertainty in the determination of LTG in human plasma by LC-MS/ MS is mainly caused by the protein precipitation recovery,matrix effect and sample preparation at low concentration, and by the matrix effect,sample preparation and repeatability at high concentration.
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Objective:To establish an HPLC-MS/MS method for the determination of lamotrigine ( LTG) in human plasma to be applied in the clinical therapeutic drug monitoring. Methods:LTG was analyzed on a Kromasil C8 (50 mm × 2. 1 mm,5μm) column. Methanol and water (both containing 0. 1% formic acid) was used as the mobile phase with gradient elution. The flow rate was 0. 6 ml ·min-1 at the column temperature of 40℃. The ion transitions under an ESI positive model were performed at m/z 256. 0>211. 0 and m/z 264. 1>154. 0 for LTG and ticlopidine (internal standard, IS), respectively. Results: The calibration curve of LTG was linear within the range of 0. 02-2 μg · ml-1 . The recoveries of LTG at three quality control levels were within the range of 91. 94%-100. 28%. LTG was stable under all tested conditions and the dilution (the dilution factor was 10) had no influence on the accuracy and precision of LTG determination. Conclusion:The HPLC-MS/MS method for the determination of LTG developed in the study is accuracy, stable and convenient, and is applicable in the clinical therapeutic drug monitoring of LTG.