PDF(Pubmed)
Abstract：
Cystinosis is a rare lysosomal storage disorder caused by autosomal recessive mutations in the CTNS gene that encodes for the cystine transporter cystinosin, which is expressed on the lysosomal membrane mediating the efflux of cystine. Cysteamine bitartrate is a cystine-depleting aminothiol agent approved for the treatment of cystinosis in children and adults. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of cysteamine levels in plasma samples. This LC-MS/MS method was validated according to the European Medicines Agency (EMA)\'s guidelines for bioanalytical method validation. An ultra-performance liquid chromatograph (UPLC) coupled with a 6470 mass spectrometry system was used for cysteamine determination. Our validated method was applied to plasma samples from n = 8 cystinosis patients (median, interquartile range (IQR) = 20.5, 8.5-26.0 years). The samples were collected before cysteamine oral administration (pre-dose) and 1 h after (post-dose). Our bioanalytical method fulfilled the regulatory guidelines for method validation. The cysteamine plasma levels in pre-dose samples were 2.57 and 1.50-3.31 μM (median and IQR, respectively), whereas the post-dose samples reported a cysteamine median concentration of 28.00 μM (IQR: 17.60-36.61). Our method allows the rapid determination of cysteamine plasma levels. This method was successfully used in cystinosis patients and, therefore, could be a useful tool for the evaluation of therapy adherence and for future pharmacokinetic (PK) studies involving a higher number of subjects.
摘要：
胱抑素病是一种罕见的溶酶体贮积症，由编码胱氨酸转运蛋白的CTNS基因的常染色体隐性突变引起，在溶酶体膜上表达，介导胱氨酸的外排。半胱胺重酒石酸盐是一种消耗胱氨酸的氨基硫醇药物，已被批准用于治疗儿童和成人的胱氨酸病。在这项研究中,我们开发并验证了液相色谱-串联质谱（LC-MS/MS）方法，用于测定血浆样品中的半胱胺水平。该LC-MS/MS方法根据欧洲药品管理局(EMA)的生物分析方法验证指南进行验证。超高效液相色谱仪（UPLC）与6470质谱系统耦合用于半胱胺测定。我们经过验证的方法应用于n=8例膀胱炎患者的血浆样本(中位数，四分位数间距（IQR）=20.5，8.5-26.0年）。在半胱胺口服给药之前(给药前)和给药后1小时(给药后)收集样品。我们的生物分析方法符合方法验证的监管指南。给药前样品中的半胱胺血浆水平为2.57和1.50-3.31μM（中位数和IQR，分别)，而给药后样本报告半胱胺的中值浓度为28.00μM(IQR:17.60-36.61).我们的方法可以快速测定半胱胺血浆水平。该方法已成功用于膀胱炎患者，因此,可能是评估治疗依从性和未来涉及更多受试者的药代动力学（PK）研究的有用工具。
