title: Quantitative determination and validation of avermectin B1a in commercial products using quantitative nuclear magnetic resonance spectroscopy.
abstract: Nuclear magnetic resonance is defined as a quantitative spectroscopic tool that enables a precise determination of the number of substances in liquids as well as in solids. There is few report demonstrating the application of NMR in the quantification of avermectin B1a (AVB1a ); here, a proton nuclear magnetic resonance spectroscopy ((1) H NMR) using benzene [1-methoxy-4-(2-nitroethyl) (PMN)] as an internal standard and deuterochloroform as an NMR solvent was tested for the quantitative determination of AVB1a . The integrated signal of AVB1a at 5.56 ppm and the signal of PMN at 8.14 ppm in the (1) H NMR spectrum were used for quantification purposes. Parameters of specificity, linearity, accuracy, precision, intermediate precision, range, limit of detection (LOD), limit of quantification (LOQ), stability and robustness were validated. The established method was accurate and precise with good recovery (98.86%) and relative standard deviation (RSD) of assay (0.34%) within the linearity of the calibration curve ranging from 5.08 to 13.58 mg/ml (R(2)  = 0.9999). The LOD and LOQ were 0.009 and 0.029 mg/ml, which indicated the excellent sensitivity of the method. The stability of the method was testified by a calculated RSD of 0.11%. The robustness was testified by modification of four different parameters, and the differences among each parameter were all less than 0.1%. Comparing with the assay described by the manufacturer of avermectin tablets, there was no significant difference between the assay obtained by HPLC and quantitative NMR (qNMR), which indicated qNMR was a simple and efficient method for the determination of AVB1a in commercial formulation products.
authors.affiliation: Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, China.
authors.forename: Zhuoni
authors.initials: Z
authors.lastname: Hou
authors.forename: Xianrui
authors.initials: X
authors.lastname: Liang
authors.forename: Liping
authors.initials: L
authors.lastname: Du
authors.forename: Feng
authors.initials: F
authors.lastname: Su
authors.forename: Weike
authors.initials: W
authors.lastname: Su
mesh_terms: D000871:Anthelmintics / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D007202:Indicators and Reagents; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000032:analysis; D057230:Limit of Detection; D009682:Magnetic Resonance Spectroscopy; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D000871:Anthelmintics; D007202:Indicators and Reagents; C022120:avermectin B(1)a; D007559:Ivermectin
keywords: 1H NMR; NMR; avermectin B1a; commercial products; drug validation; quality control; quantitative NMR