Fampridine (dalfampridine) is used to improve walking in people who have multiple sclerosis (a disease in which the nerves do not function properly and may cause weakness, numbness, loss of muscle coordination and problems with vision, speech and bladder control). Measurement of fampridine plasma concentrations is not practical at sites lacking the facilities to prepare and process blood samples. A dried blood spot (DBS) sampling method, in which a few drops of blood, drawn by lancet from the finger, are applied onto specially manufactured absorbent filter paper, can be used as an alternative to plasma monitoring and would allow for simplified sample storage and transport. Using blood samples from pharmacokinetic studies, an ultra-high performance liquid chromatography assay method for quantification of fampridine in DBS is developed and validated for specificity, selectivity, accuracy, precision, reproducibility and stability. Method was specific and selective relative to endogenous compounds, with required process efficiency, and no matrix effect. Inaccuracy and precision for intra-day and inter-day analyses were tested at all concentrations. Quantification of fampridine in DBS assay was not affected by blood deposit volume and punch position within spot, and hematocrit level had a limited but acceptable effect on measurement accuracy. Fampridine was stable for at least 2 months at room temperature. The correlation between DBS and plasma concentrations with an average blood-to-plasma ratio is determined. DBS sampling is a simple and practical method for monitoring fampridine concentrations. The method is completely validated as per ICH guidelines and extended to the in vivo determination of fampridine in male albino rats.

中文翻译：

---

使用干血斑 (DBS) 方法学进行 Fampridine 生物分析的超高效液相色谱方法：在白化大鼠药代动力学研究中的应用

Fampridine (dalfampridine) 用于改善多发性硬化症患者的行走能力（一种神经功能不正常的疾病，可能导致虚弱、麻木、肌肉协调性丧失以及视力、言语和膀胱控制问题）。在缺乏制备和处理血样的设施的地方，测量范吡啶血浆浓度并不实用。干血点 (DBS) 采样方法，即用刺血针从手指上抽取几滴血液，涂在特制的吸收性滤纸上，可用作血浆监测的替代方法，并可简化样本存储和运输。使用药代动力学研究的血液样本，开发了一种用于定量 DBS 中 fampridine 的超高效液相色谱测定方法，并验证了其特异性、选择性、准确性、精密度、重现性和稳定性。该方法相对于内源性化合物具有特异性和选择性，具有所需的工艺效率，且无基质效应。在所有浓度下测试了日内和日间分析的不准确度和精确度。DBS 测定中苯吡啶的定量不受点内血沉积量和打孔位置的影响，血细胞比容水平对测量精度的影响有限但可接受。芬吡啶在室温下可稳定至少 2 个月。确定 DBS 和血浆浓度与平均血液与血浆比率之间的相关性。DBS 采样是一种简单实用的监测 fampridine 浓度的方法。该方法根据 ICH 指南进行了完全验证，并扩展到雄性白化大鼠体内 fampridine 的测定。