Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
Eur J Pharm Sci. 2011 Apr 18;42(5):568-77. doi: 10.1016/j.ejps.2011.02.010. Epub 2011 Mar 5.
Crystallization of lactose from 10% (w/v) aqueous solutions was investigated with the use of polar antisolvents. Crystal growth was observed at 50-65% antisolvent content and showed a morphological transition from a polyhedral to needle-like habit with increasing antisolvent content, which coincided with a polymorphic transition from alpha lactose monohydrate (Lα·H(2)O) to beta lactose (Lβ). Where dehydrating antisolvents were employed such as methanol and ethanol, evidence of Lα·H(2)O dehydration to form Lα(S) was also observed at 95% antisolvent content. Powder X-ray diffraction (PXRD) analysis of the crystals highlighted the preferred orientation effects exhibited by large crystals of this kind, indicating the difficulties experienced by the non-specialist when performing phase identification of lactose polymorphs. The same studies were applied to raffinose pentahydrate, trehalose dihydrate and mannitol to assess the effects of crystallization conditions on other pharmaceutical excipients.
从 10%（w/v）的水溶液中用极性抗溶剂研究了乳糖的结晶。在 50-65%抗溶剂含量下观察到晶体生长，并表现出从多面体形貌向针状形貌的形态转变，随着抗溶剂含量的增加，这与从α-乳糖一水合物（Lα·H2O）到β-乳糖（Lβ）的多晶型转变相一致。当使用甲醇和乙醇等脱水抗溶剂时，在 95%抗溶剂含量下也观察到 Lα·H2O 脱水形成 Lα（S）的证据。晶体的粉末 X 射线衍射（PXRD）分析突出了这种大晶体表现出的优先取向效应，表明非专业人员在进行乳糖多晶型物的相鉴定时所面临的困难。同样的研究也应用于棉子糖五水合物、海藻糖二水合物和甘露醇，以评估结晶条件对其他药用辅料的影响。
