Quantization Methods Of Two Macrolide Antibiotics In Human Plasma And Their Application In Pharmacokinetic Studies

Two specific and sensitive LC-MS/MS methods were developed to determine two Macrolide Antibiotics in human plasma. The methods were successfully used in their Pharmacokinetic studies.1.Determination of Azithromycin in human plasma by liquid chromatography一tandem mass spectrometryA liquid chromatographic-tandem mass spectrometric method WasDeveloped for the analysis of Azithromycin in human plasma. Take roxithromycin as internal stand. The human plasma was extracted by acetic ether after alkalify, then separated on a Ultimate XB-C₁₈ column. The mobile phase consisted of methanol-0.1% ammonium acetate and 0.1% acetic acid buffer (82:18,v/v). The linear calibration curve over the range of 1.075¹075μg·L^-1; the lower limit of quantification was1.075μg·L^-1; the QC samples(2.58μg·L^-1,43.0μg·L^-1,645μg·L^-1)have good reproducibility and accuracy, the intra-day RSD and inter-day RSD were below 15%; the extraction recovery were 74.63%～101.19%; the matrix effect were 94.80%～103.75%. the samples of Azithromycin were stability in different conditions. The main parameters obtained after an oral dose of 500mg Azithromycin to18 Chinese volunteers were as follows: Cmax was found to be(458.833±243.535)μg·L^-1 , Tmax was observed (3.111±1.323)h,the value of t1/2 was (56.807±17.614)h ,CL was to be (127.12±64.75)L/h,Vz was (10639.64±6624.59)L, AUC_0-t was (4443.21±1958.76)μg/L*h and AUC_0-∞(4822.84±2256.66)μg/L*h.The method is proved to be specificity,speed,sensitivity and suitable for clinical investigation of Azithromycin pharmacokinetics.2.Determination of Clarithromycin in human plasma by liquid chromatography一tandem mass spectrometry A sensitivity and speed LC-MS/MS method was developed for determined of Clarithromycin leves in human plasma. Take roxithromycin as internal stand. The human plasma was extracted by acetic ether after alkalify, then separated on a Ultimate XB-C₁₈ column. The mobile phase consisted of methanol-0.05% ammonium acetate and 0.1% acetic acid buffer (65:35,v/v). The linear calibration curve over the range of 10⁴000μg·L^-1, the lower limit of quantification was10μg·L^-1; the QC samples(25μg·L^-1,250μg·L^-1,3000μg·L^-1)have good reproducibility and accuracy, the intra-day RSD and inter-day RSD were below 15%; the extraction recovery were 65.23%～99.81%; the matrix effect were 97.68%～108.33%. the samples of Azithromycin were stability in different conditions. The main parameters obtained after an oral dose of 500mg Clarithromycin to 20 Chinese volunteers were as follows: Cmax was found to be (1745.03±731.43)μg·L^-1 ,Tmax observed was (2.03±0.638)h,the value of t1/2 was(4.58±0.82)h; CL was (42.90±26.29)L/h; Vz was (282.00±185.72)L; AUC_0-t was(14341.1±5960.62)μg·L^-1*h, AUC_0-∞ was(14898.51±6379.53)μg/L*h. The method was proved to be speed,sensitivity and suitable, one sample is only take 4 min, and successfully utilized for oral Clarithromycin clinical studies.