| Lithium Carbonate is an antipsychotic drug with high application value,which can not only effectively control mania,but also relieve bipolar affective disorder and prevent its recurrence.When ingested,lithium carbonate performs its therapeutic functions in the form of lithium ions.However,due to the low therapeutic index of lithium salts and the closeness between toxic dose and therapeutic dose,it is very important to accurately measure the concentration of lithium ions in plasma when evaluating the bioequivalence and safety of such drugs.At present,the main methods for the determination of lithium-ion concentration in human plasma are Atomic Absorption Spectroscopy(AAS)method and Ion Selective Electrode(ISE)method,but both have certain limitations.Based on ICP-MS(Inductively Coupled Plasma Mass Spectrometry)technology,a method for the analysis of lithium-ion concentration in human body was established in this study.The method is sensitive,accurate and rapid that can meet the needs of mass sample test.The main research results are as follows:1.Establishment and evaluation of the ICP-MS method for the test of lithium-ion concentration in human plasma.Plasma samples were treated by direct dilution method.Sample collection parameters are as follows:Mode is STD,Uptake Time is 60 s,Wash Time is 120 s and Dwell time is 0.01 s.The instrument parameters are as follows:argon flow rate is 0.8 L/min,cooling gas flow rate is 14 L/min,peristaltic pump speed is 40 rpm,plasma power is 1150 W,sample depth is 5 mm and atomizing chamber temperature is 2.7℃.The results showed that the method had good selectivity and there was no interference between analyte and internal standard(IS),so the testing results were not interfered by endogenous substances in plasma.The standard curve of lithium ion depicted by this method ranges from 80 to 4000 ng/mL,and the linear relationship is good(r2>0.98).The intra-and inter-batch accuracy deviations ranged from-7.5%to 8.1%for the high,medium and low concentration levels,-11%to 10.8%for the Lower Limit of Quantitation(LLOQ),1.3%to 4.5%for the high,medium and low concentration levels,and 0.6%to 6.5%for LLOQ.The extraction recoveries(ER)of high,medium and low concentrations of lithium ion were 93.0%-95.6%.The working solution and matrix samples containing analytes have good stability at room temperature.After five freeze-thaw cycles at-80℃ and-20℃,the matrix samples were stable according to the test of this method.The matrix samples containing the analytes can be frozen for 91 days at-80℃ and 52 days at-20℃.The treated samples have good stability and reproducibility when stored at room temperature.In summary,the verification results showed that this study was in line with the fourth General Rule of Chinese Pharmacopoeia(2020)"9012 Guiding Principles for the Verification of Quantitative Analysis Methods of Biological Samples".2.Bioequivalence of the two preparations tested by ICP-MS.The established method was used to determine the plasma samples of 35 healthy subjects taking the test preparation and reference preparation on an empty stomach.A total of 2940 test samples were tested,and the reanalysis results of 211 test samples met the acceptance criteria,with a passing rate of 96.7%,indicating that the method has good accuracy and reproducibility.The residual rates of the analytes were all less than 16.9%,and those of the IS were all less than 0.3%,indicating that the interference of the method was relatively low.The linear fitting is good,and all R2 values are greater than 0.9848.RSD of low-concentration,medium-concentration and high-concentration quality control(QC)samples in the sample analysis batch ranged from 4.6%to 5.7%,and the average accuracy deviation ranged from 1.2%to 4.0%,indicating that the method had good accuracy and precision,and the tested data were reliable.In conclusion,the method has low interference,high precision,good sensitivity,good repeatability and accurate and reliable data in practical application.Three bioequivalence evaluation methods were used to evaluate the two preparations,and the results showed that the two preparations were bioequivalent.In this study,a method for the accurate and rapid test of lithium-ion content in human plasma samples based on ICP-MS was successfully established and verified,and the method was successfully applied to the bioequivalence study of test preparations and reference preparations of lithium carbonate tablets(250 mg)... |
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