UPLC-MS/MS法检测抗菌乳膏中的痕量地塞米松和倍他米松

目的：建立抗菌乳膏药物中痕量地塞米松和倍他米松的超高效液相色谱-串联质谱定性定量分析方法。方法：以泼尼松为内标，抗菌乳膏样品经处理后加乙腈提取，提取液经HLB固相萃取小柱纯化富集，进样2 μL测定。色谱柱：Shim-pack XR-ODS Ⅲ（1.6 μm，50 mm×2.0 mm），流动相：乙腈-水，梯度洗脱，流速0.4 mL·min^-1，分析时间14 min；采用电喷雾离子源（ESI+）、多反应监测模式（MRM），地塞米松和倍他米松定量离子对为m/z 393.2→373.0，内标泼尼松离子对为m/z 359.2→146.9。结果：地塞米松和倍他米松在1~41 ng·mL^-1浓度范围内线性关系良好，定量限为12.5 μg·kg^-1，检出限为5 μg·kg^-1，方法回收率为100%~108%。结论：本方法可用于抗菌乳膏药物中痕量地塞米松和倍他米松的监测。

Objective: To establish a method for the trace analysis of dexamethasone and betamethasone in creams of antimicrobial agent using ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). Methods: Prednisone was treated as an internal standard, and the treated sample was extracted with acetonitrile being added for twice. The merged extraction was purified by a HLB solid phase extraction(SPE)cartridge and separated by a column of Shim-pack XR-ODSⅢ(1. 6 μm, 50 mm×2. 0 mm)with acetonitrile-water as mobile phase in gradient elution. The analysis was performed using an electrospray ionization in positive mode(ESI+)and the multiple-reaction monitoring(MRM)mode with the transition of m/z 393. 2→373. 0 monitored for dexamethasone and betamethasone and the transition of m/z 359. 2→146. 9 monitored for prednisone. Results: The method showed a good linearity in the range of 1-41 ng·mL^-1. Limits of quantitation(LOQ)and detection(LOD)of this method were 12. 5μg·kg^-1 and 5μg·kg^-1, respectively. Recoveries of the method were from 100 to 108%. Conclusion: This method can be used for determination of trace dexamethasone and betamethasone in creams of antimicrobial agent.