Desenvolvimento de método analítico por cromatografia líquida para determinação de impurezas no iodixanol

Abstract

This work describes for the first time an isocratic method in a single analytical run to quantify deacetyl iodixanol (iodixanol related compound C), iopentol (iodixanol related compound D) and cyclized iodixanol (iodixanol related compound E), as impurities in iodixanol. Iodixanol is a drug substance, dimeric, nonionic, water-soluble, used as a radiographic contrast medium, which is administered by intravascular injection. The impurities A and B were not evaluated in this work, since they are not commercially available as standards. The method was also validated for the quantitative assay, since there is no chromatographic method described in the current USP compendium for the assay. The impurities can be formed during the synthesis process of iodixanol, and it is important to quantify them due to their related toxicity. In this work, the reverse and hydrophilic interaction (HILIC) modes of elution were evaluated. The hydrophilic elution mode was selected due to good efficiency and selectivity. In both modes of elution, columns having the technology fused-core were used, since they demonstrate high efficiency due to their better mass transfer in comparison to conventional HPLC columns. The chromatographic separation was carried out on a kinetex® HILIC column (150 x 4.6 mm; 2.6 μm) at 20 °C using acetonitrile-formic acid (pH 3.2; 1.0 mmol L-1) (92:08, v/v) at a flow rate of 0.8 mL/min. The compounds were monitored at 243 nm and the total time of analysis was 45 min. The method was validated in accordance with the current ICH guidelines for determination of impurities which include selectivity, linearity, accuracy, precision, limits of quantification and detection and robustness. The limits of quantification (LOQ) were 0.479; 0.0606 and 0.133 μg/mL for the impurities C, D and E, respectively. Furthermore, the validated methods were tested in iodixanol samples. The test results of the analyses of impurities and assay in those samples are presented and discussed accordingly.