Publication details
Affinity capillary electrophoresis of human serum albumin and small molecules a comparison between mobility shift and frontal analysis
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| Year of publication | 2019 |
| Type | Conference abstract |
| Citation | |
| Description | The estimation of a molecules’ affinity towards a target plays a crucial role in the early stages of pharmaceutical development. Therefore, high quality ligand binding assays are very important. Capillary Electrophoresis - Frontal Analysis (CE-FA) and Mobility Shift Affinity Capillary Electrophoresis (ms ACE) are the most commonly used modes of free solution Affinity Capillary Electrophoresis. In this study, the precision and accuracy of both assays were evaluated and compared. The interaction of small drugs and human serum albumin was used as a model system. The association constant of several standard drugs towards albumin was independently measured by three analysts with both assays. The deviations between the estimated constants within one assay were used to rate its reproducibility. The divergences of the mean measurement results among the different assays were employed to assess the accuracy. It could be shown, that CE-FA is well suited to measure the negatively charged drug ibuprofen and the low affinity drug lidocaine. The binding parameter could be determined with a relative standard deviation (RSD) lower than 30%. In contrast; CE-FA was less suitable to measure carbamazepine and amlodipine. Fortunately, these interactions could easily be determined using ms ACE. Here, the maximal variability of the association constants ranged between 21 and 27 % RSD. In general, the CE-FA mode proved to be the more reliable ligand binding assay for these model systems. However, in specific cases, such as the analysis of low soluble drugs like carbamazepine, ms ACE showed a superior performance. It can therefore be concluded that these two techniques complement each other well and are therefore valuable analytical tools. |