Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; School of Pharmacy, University of Eastern Finland, 70210 Kuopio, Finland.
Int J Pharm. 2022 Apr 5;617:121581. doi: 10.1016/j.ijpharm.2022.121581. Epub 2022 Feb 14.
Biomaterial aerogel fabrication by freeze-drying must be further improved to reduce the costs of lengthy freeze-drying cycles and to avoid the formation of spongy cryogels and collapse of the aerogel structures. Residual water content is a critical quality attribute of the freeze-dried product, which can be monitored in-line with near-infrared (NIR) spectroscopy. Predictive models of NIR have not been previously applied for biomaterials and the models were mostly focused on the prediction of only one formulation at a time. We recorded NIR spectra of different nanofibrillated cellulose (NFC) hydrogel formulations during the secondary drying and set up a partial least square regression model to predict their residual water contents. The model can be generalized to measure residual water of formulations with different NFC concentrations and the excipients, and the NFC fiber concentrations and excipients can be separated with the principal component analysis. Our results provide valuable information about the freeze-drying of biomaterials and aerogel fabrication, and how NIR spectroscopy can be utilized in the optimization of residual water content.
通过冷冻干燥制造生物材料气凝胶必须进一步改进，以降低漫长的冷冻干燥周期的成本，并避免形成海绵状冷冻凝胶和气凝胶结构的塌陷。残余含水量是冷冻干燥产品的一个关键质量属性，可以使用近红外（NIR）光谱进行在线监测。NIR 的预测模型以前没有应用于生物材料，而且这些模型主要集中在一次预测一种配方上。我们在二次干燥过程中记录了不同纳米原纤化纤维素（NFC）水凝胶配方的 NIR 光谱，并建立了偏最小二乘回归模型来预测它们的残余含水量。该模型可以推广到测量具有不同 NFC 浓度和赋形剂的配方的残余水，并且可以使用主成分分析分离 NFC 纤维浓度和赋形剂。我们的结果提供了有关生物材料冷冻干燥和气凝胶制造的有价值的信息，以及近红外光谱如何用于优化残余水含量。
