Mallu Useni Reddy, Anna Venkateswara Rao, Kasimala Bikshal Babu
Koneru Lakshmaiah Education Foundation, Department of Chemistry, Guntur, Andhra Pradesh, India.
Turk J Pharm Sci. 2019 Dec;16(4):457-465. doi: 10.4274/tjps.galenos.2018.34635. Epub 2019 Nov 11.
Leflunomide (LFNM) is a drug that belongs to isoxazole derivatives and has immunosuppressive and anti-inflammatory activities. A literature search confirms that there is no method reported for the simultaneous estimation of LFNM and its related impurities A and B in pharmaceutical dosage forms or in bulk drug. Hence the present work aimed to develop a simple stability indicating RP-HPLC method for the separation and quantification of LFNM and its impurities A and B.
Systematic trials of method conditions like mobile phase ratio, pH, flow rate, stationary phase, and detector wavelength were performed for the simultaneous analysis of LFNM and its related impurities A and B. The developed method was validated as per the ICH guidelines including forced degradation studies in different stress conditions.
Optimized separation was achieved on a Thermo Scientific Hypersil ODS C18 column (250 mm×4.6 mm; 5 μm id) using mobile phase composition of acetonitrile, methanol, and 0.1 M sodium perchlorate in the ratio of 40:30:30 (v/v), pH 4.6, at a flow rate of 1.0 mL/min in isocratic elution. UV detection was carried out at a wavelength of 246 nm. Well-resolved peaks were observed with high numbers of theoretical plates, lower tailing factor, and reproducible relative retention time and response factor. The method was validated and all the validation parameters were found to be within the acceptance limits. Stability tests were done through exposure of the analyte solution to five different stress conditions, i.e. 1 N HCl, 1 N NaOH, 3% HO, thermal degradation of powder, and exposure to UV radiation. The method can successfully separate the degradation products along with both the impurities studied. The % degradation was also found to be less.
The method developed for LFNM is simple and precise and can be applied for the separation and quantification of LFNM and its related impurities in bulk drug and pharmaceutical formulations.
来氟米特（LFNM）是一种异恶唑衍生物类药物，具有免疫抑制和抗炎活性。文献检索证实，尚无关于同时测定药物剂型或原料药中来氟米特及其相关杂质A和B的方法报道。因此，本研究旨在开发一种简单的稳定性指示反相高效液相色谱法，用于分离和定量来氟米特及其杂质A和B。
对流动相比例、pH值、流速、固定相和检测波长等方法条件进行系统试验，以同时分析来氟米特及其相关杂质A和B。所开发的方法按照国际协调会议（ICH）指南进行验证，包括在不同应激条件下的强制降解研究。
使用乙腈、甲醇和0.1 M高氯酸钠以40:30:30（v/v）的比例组成的流动相，pH值为4.6，流速为1.0 mL/min进行等度洗脱，在Thermo Scientific Hypersil ODS C18柱（250 mm×4.6 mm；内径5μm）上实现了优化分离。在246 nm波长处进行紫外检测。观察到峰分离良好，理论塔板数高，拖尾因子低，相对保留时间和响应因子可重现。该方法经过验证，所有验证参数均在可接受范围内。通过将分析物溶液暴露于五种不同的应激条件下进行稳定性试验，即1 N盐酸、1 N氢氧化钠、3%过氧化氢、粉末的热降解以及紫外辐射暴露。该方法能够成功分离降解产物以及所研究的两种杂质。降解百分比也较低。
所开发的来氟米特分析方法简单且精确，可用于原料药和药物制剂中来氟米特及其相关杂质的分离和定量。
