Validation of a Serum Analysis Method to Analyze Antihistamines by Capillary Electrophoresis

The validation of an electrophoresis-based analytical method to quantify 17 antihistamines in pharmaceutical formulations and serum is described. Then, whether the methodology provides true values with low uncertainty and is able to detect the concentration range level of analyte usually found in the matrix was evaluated. The analytical method was validated following the recommendations of an official guide to provide more reliability to the results. The ICH Harmonized Tripartite Guideline was selected because it was especially developed for analysis of drugs. The guide and the following required validation parameters, selectivity, calibration range, linearity, limit of detection, limit of quantification, inter- and intraday accuracy and precision, and robustness, were described. The method was inexpensive, fast, simple, environmentally friendly, and useful for routine analysis. The methodology was successfully validated and applied to commercial pharmaceutical formulations and spiked blank serum samples. 1. Introduction Antihistamines are widely used to provide relief of allergic symptoms caused by histamine release. They are administered as decongestants for the treatment of coughs, colds, and allergies [1]. Structurally, antihistamines are substituted ethylamines [2, 3]. The structure can be seen in Figure 1. In order to prescribe the adequate dose of antihistamines, the accurate amount of analytes in pharmaceutical formulations has to be known. Moreover, the measurement of the concentration of antihistamines in blood is useful to study the way of metabolization of the compounds. Therefore, the development of an analytical methodology to quantify antihistamines in pharmaceutical formulations is of the utmost importance to study their effects on the human body [4]. Figure 1: Structure of the antihistamines. Recently, a capillary electrophoresis method has been proposed to detect antihistamines in pharmaceuticals and blood [3]. This method proposes an easy sample preparation: the solubilization of pharmaceutical formulations and serum in a micellar solution. The main electrophoresis conditions (capillary length, pH buffer, buffer concentration, injection pressure, applied voltage, and UV) were optimized. This method show important advantages, as low cost, high separation efficiency, short analysis times, low operational costs, and fast method development [3]. Once the methodology was developed, it was validated to prove that it was suitable for its intended purpose: the reliable quantification of antihistamines in pharmaceuticals and blood with