Near-infrared for on-line determination of quality parameter of Sophora japonica L. (formula particles): From lab investigation to pilot-scale extraction process

Background: Extraction process of dried flowers of formula particles should be investigated from lab investigation to pilot‑scale because of good water absorbing capacity and obscure active pharmaceutical ingredients (API) dissolution. Objective: Reliable analysis of on‑line near‑infrared (NIR) technique and novel application in fascinating modern, traditional Chinese medicine production (formula particles) was proved. Materials and Methods: The extraction process of Sophora japonica L. (formula particles) was used as an example, the rutin was regarded as API. On‑line NIR technology was used to monitor the variation of rutin in the extraction process. High‑performance liquid chromatography (HPLC) was used as a reference method to determine the content of rutin during the extraction process. The sample set was selected by Kennard‑Stone (KS) algorithm. Different pretreatment methods were compared. The synergy interval partial least square (SiPLS) algorithm was applied. Chemometrics indicators and multivariate detection limits method were mutually used to assess the model. Results: According to both errors α (0.05) and β (0.05), rutin content could be detected by on‑line NIR, which was more than 0.181 mg/mL. Conclusions: This work demonstrated the feasibility of NIR for on‑line determination of rutin in the pilot‑scale extraction process of S. japonica. L. It provided technical support for the NIR application in the extraction process of formula particles.