To establish an 1H quantitative nuclear magnetic resonance (1H qNMR) method for determination of noracetildenafil.
1H qNMR spectra were obtained in CDCL3 by using Bruker Ascend 600 spectrometer with noesyigld1d pulse sequence, the relaxation delay time was 30 s, and 32 scans were recorded.
The signals δ8.15 and 9.14 of noracetildenafil and δ6.09 of 1,3,5-Trimethoxybenzene were used for quantitation. Linear regression of areas ratio (As/Ar) versus mass ratio (Ws/Wr) of δ8.15 and 6.09 yielded a correlation coefficient of 0.999 1 and regression equation of y=0.119 7x+0.003 4, the replicability RSD was 1.66% (n=5), the repeatability RSD was 0.76% (n=5), and the determined content was 97.48%. Linear regression of areas ratio (As/Ar) versus mass ratio (Ws/Wr) at δ9.14 and 6.09 yielded a correlation coefficient of 0.999 1 and regression equation of y=0.116 8x+0.004 5, the replicability RSD was 1.69% (n=5), the repeatability RSD was 0.43% (n=5), and the content of noracetildenafil was 95.35%. The result determined by 1H qNMR method (96.42%) was consistent with the results by mass balance method (96.54%) and HPLC assay method (97.07%).
The established 1H qNMR method can be used for the quantitative determination of noracetildenafil. It is accurate and rapid and could be complementary with the mass balance method for the assay of reference substances.
| 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 |