To establish a stable and reliable gas chromatography-tandem mass spectrometry method for the determination of N-nitrosodimethylamine (NDMA) in metformin hydrochloride sustained-release tablets, and to optimize extraction conditions by investigating the effects of isopropyl alcohol and thioglycerin on the stability of the tested solution.
Separation was achieved on AB-InoWax capillary column (30 m×0.25 mm×0.25 μm) with polyethylene glycol as the stationary phase. Electron ion(EI) source and multiple reaction monitoring (MRM) mode were used. Quantitative determination was performed by both external standard and internal standard.
The addition of thioglycerin could significantly improve the stability of the test solution. NDMA showed good linearity within the concentration range of 0.25-50 ng·mL-1(r>0.999). The detection limit of the method was 0.1 ng·g-1 and the quantification limit of the method was 0.2 ng·g-1. The average recoveries (n=9) were 97.3% and 94.9% while using external standard and internal standard, respectively. Precision, repeatability and stability were good with RSD less than 8%. Ninety batches of metformin hydrochloride sustained release tablets were tested. NDMA content in all detected samples were all less than 30% of the acceptable limit set by the National Medical Products Administration and FDA.
This method shows satisfactory sensibility, specificity, accuracy, stability and durability, which is suitable for quantitative analysis of NDMA in metformin hydrochloride sustained-release tablets, providing technical support for the quality and safety of related products.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |