³¹P核磁共振内标法测定甘油磷酸胆碱的含量

目的：建立核磁共振磷谱定量法（³¹PqNMR）测定三类新药甘油磷酸胆碱（glycerophosphocholine，GPC）中GPC的绝对含量。方法：选择磷酸三苯酯（triphenyl phosphate，TPP）为内标，以其谱峰（δ-17.0）为内标峰，待测物定量峰化学位移在δ0.56处，溶剂为MEOD-d₄。结果：通过考察NMR实验条件的影响，选择采样次数NS为32次，弛豫延迟时间D₁为20.0 s，脉冲宽度P₁为9.8μs。（样品/内标）质量比对NMR峰面积比的零截距标准曲线斜率与理论值非常接近，线性回归系数r=0.996 7，重复性实验测得RSD为0.27%；核磁共振法测得GPC99药物中GPC的含量为99.67%，在无基准物质作对照的情况下，比HPLC-MS外标法（94.57%）更准确。结论：采用³¹P qNMR方可测定甘油磷酸胆碱的含量，且此方法简单易行、结果准确。

Objective: To determine the content of Glycerophosphocholine(GPC) in its tablet, a quantitative ³¹P nuclear magnetic resonance(³¹P qNMR) approach was presented.Methods: Triphenyl phosphate(TPP) was chosen as an internal standard and its ³¹P NMR peak at δ-17.0 as the internal standard peak.Quantitative NMR peak of GPC was selected at δ0.56.Deuterated methanol was used as solvent.Results: The optional conditions were selected as follows:number of scan (NS):32, relaxation delay time(D₁):20 s, 90° pulse width(P₁):9.8 μs.A good linear relationship between weight ration and peak area ratio of the internal standard TPP to GPC with correlative coefficient of 0.996 7;Results: The content of GPC determined by ³¹P qNMR was 99.67%, which was more accurate than the results of HPLC-MS(94.57%).Conclusions: This method is specific, accurate, simple, and it is suitable for the quantitative determination of the reference substance content.This method can be used for the determination of the content of GPC.