Blanco M, Alcalá M, Bautista M
Departament de Química, Unitat de Química Analítica, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain.
Eur J Pharm Sci. 2008 Apr 23;33(4-5):409-14. doi: 10.1016/j.ejps.2008.01.011. Epub 2008 Feb 2.
Near infrared spectroscopy has proved highly suitable for the analysis of pharmaceutical formulations. However, its limited sensitivity can severely restrict its scope of application. In this work, we determine the active principle and two preservatives in a pharmaceutical preparation available as a hydrogel. The matrix of the pharmaceutical preparation exhibits strong absorption in the NIR spectral region; also, the two preservatives (parabens) are very similar in chemical and spectral terms, and present at low concentrations in the pharmaceutical. These complications make it rather difficult to accurately quantify the active principle and the preservatives, which can only be accomplished by using an effective design in order to prepare the samples to be included in the calibration set and select the optimum spectral range for measuring each analyte. The evaporation of solvents during the measurement process produces increasing errors related with sample's air exposition; the introductions of new samples with a wider range of the volatile components correct this effect. An ANOVA of the predictions obtained with the new models shows that correct the error due to evaporation. The proposed method was validated for the analytical control of the studied preparation.
近红外光谱已被证明非常适合用于药物制剂的分析。然而，其有限的灵敏度会严重限制其应用范围。在这项工作中，我们测定了一种以水凝胶形式存在的药物制剂中的活性成分和两种防腐剂。该药物制剂的基质在近红外光谱区域表现出强烈吸收；此外，两种防腐剂（对羟基苯甲酸酯）在化学和光谱方面非常相似，且在药物中的浓度较低。这些复杂情况使得准确量化活性成分和防腐剂相当困难，这只能通过采用有效的设计来实现，以便制备校准集中包含的样品，并为测量每种分析物选择最佳光谱范围。测量过程中溶剂的蒸发会产生与样品暴露于空气中相关的越来越大的误差；引入具有更广泛挥发性成分范围的新样品可纠正这种影响。对新模型获得的预测结果进行方差分析表明，可纠正因蒸发导致的误差。所提出的方法经过验证可用于所研究制剂的分析控制。
