REQUIMTE, Toxicology Department, Faculty of Pharmacy, University of Porto, Rua Aníbal Cunha 164, 4099-030 Porto, Portugal.
J Pharm Biomed Anal. 2010 Sep 5;52(5):721-6. doi: 10.1016/j.jpba.2010.02.022. Epub 2010 Feb 23.
After the FDA's ban of ephedrine-containing supplements, Citrus aurantium appeared as an alternative to ephedra in herbal weight loss products. Synephrine, the most abundant active component of C. aurantium, exists in three different structural or positional isomeric forms (ortho-o-, meta-m-, and para-p-). Dietary supplements contain m- and p-synephrine, both alpha-adrenergic agonists,while the m-isoform is the most potent at alpha(1)-adrenoreceptors. In spite of the pharmacokinetic and toxicological interest in the study of these compounds, adequate methods for their quantification in biological samples are yet to be developed. Thus, in the present study, a sensitive gas chromatography-ion trap mass spectrometry (GC/IT-MS) method was developed and validated for the simultaneous quantitation of m- and p-synephrine in a cellular matrix after solid phase extraction (SPE). The validation of the method was performed through the evaluation of the following parameters: selectivity, linearity, specificity, precision, accuracy, limit of detection, limit of quantification, and recovery. The method's applicability was studied in two different biological matrices by evaluating p- and m-synephrine uptake in Caco-2 cells and also in freshly isolated cardiomyocytes from adult rat. The developed GC/IT-MS method was shown to be selective, accurate, precise, and valid for simultaneous determination of p- and m-synephrine in biological samples.
在美国食品和药物管理局（FDA）禁止含有麻黄碱的补充剂后，酸橙（Citrus aurantium）作为一种替代麻黄的草药减肥产品出现。辛弗林（synephrine）是酸橙中最丰富的活性成分，存在于三种不同的结构或位置异构体形式（邻位-o-、间位-m-和对位-p-）中。膳食补充剂含有 m-和 p-辛弗林，均为α-肾上腺素能激动剂，而 m-异构体在α（1）-肾上腺素受体上最有效。尽管人们对这些化合物的药代动力学和毒理学研究很感兴趣，但在生物样本中对其进行定量的充分方法尚未得到开发。因此，在本研究中，开发并验证了一种灵敏的气相色谱-离子阱质谱（GC/IT-MS）方法，用于固相萃取（SPE）后细胞基质中 m-和 p-辛弗林的同时定量。该方法的验证通过评估以下参数来进行：选择性、线性、特异性、精密度、准确性、检测限、定量限和回收率。通过评估 Caco-2 细胞中 p-和 m-辛弗林的摄取以及从成年大鼠新鲜分离的心肌细胞中的 p-和 m-辛弗林摄取，研究了该方法在两种不同生物基质中的适用性。所开发的 GC/IT-MS 方法被证明具有选择性、准确性、精密度和有效性，可用于生物样品中 p-和 m-辛弗林的同时测定。
