Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland Galway, University Road, Galway, Ireland.
J Pharm Biomed Anal. 2013 Jan;72:163-71. doi: 10.1016/j.jpba.2012.10.002. Epub 2012 Oct 12.
The detection and quantification of alternate polymorphs of active pharmaceutical ingredients (APIs), particularly at low concentrations is a key issue for the manufacture and analysis of solid-state formulations. Each polymorph can possess unique physical and chemical properties which in turn can directly affect factors such as solubility and bioavailability. Near infra-red (NIR) and Raman spectroscopies can be used for the rapid characterisation and quantification of polymorphs in solid samples. In this study we have generated a model tablet system with two excipients and a 10% API concentration, where the API is a mixture of the FII and FIII polymorphs of piracetam. Using transmission Raman spectroscopy (TRS) and NIR spectroscopy it was possible to detect FII polymorph contamination in these model tablets with limits of detection (LODs) of 0.6 and 0.7%, respectively, with respect to the total tablet weight (or ∼6-7% of the API content). The TRS method is the superior method because of the speed of analysis (∼6s per sample), better sampling statistics, and because the sharper, more resolved bands in the Raman spectra allowed for easier interpretation of the spectral data. In addition the TRS used here provides facile access to the low frequency wavenumber region for analysis of solid-state lattice modes.
检测和定量分析活性药物成分（APIs）的各种晶型，尤其是在低浓度下，是固态制剂制造和分析的关键问题。每种晶型都可能具有独特的物理和化学性质，这反过来又会直接影响溶解度和生物利用度等因素。近红外（NIR）和拉曼光谱可用于快速表征和定量分析固态样品中的晶型。在本研究中，我们生成了一个具有两种赋形剂和 10%API 浓度的模型片剂系统，其中 API 是吡拉西坦的 FII 和 FIII 晶型的混合物。使用透射拉曼光谱（TRS）和近红外光谱法，有可能检测到这些模型片剂中的 FII 晶型污染，其检测限（LOD）分别相对于片剂总重量为 0.6%和 0.7%（或 API 含量的约 6-7%）。TRS 方法是更优的方法，因为它的分析速度更快（每个样品约 6 秒），采样统计更好，并且由于拉曼光谱中更尖锐、分辨率更高的谱带，使得对光谱数据的解释更加容易。此外，这里使用的 TRS 提供了简便的方法来分析固态晶格模式的低频波数区域。
