Rapid determination of lumbrokinase potency in the earthworm extract intermediate by near-infrared spectroscopy

In traditional Chinese medicine, an extract intermediate is an extracted and purified intermediary of the production process, and its quality is crucial to the efficacy of the final product. Lumbrokinase (LK), which is found in earthworm extract intermediate, has good fibrinolysis, is an anticoagulant, provides hemorheological improvement and has other pharmacological effects, and it shows significant advantages in the treatment of thromboses. The traditional method for determining lumbrokinase potency is an agarose-fibrin plate assay, but it takes more than a dozen hours to perform and requires expensive culture medium. To develop a new method for rapidly and accurately determining the potency of lumbrokinase, near-infrared (NIR) spectroscopy combined with chemometrics is presented in this study. In addition, the variable selection combination method was investigated to optimize the modeling variables and improve the predictive abilities of the NIR model. After optimization, the parameter values of the correlation coefficient, R2c, R2p, RMSEC and RMSEP, of the partial least squares regression (PLSR) quantitative model were 0.9398, 0.9340, 289.618 U, and 538.313 U, respectively. This study demonstrates that NIR analysis techniques are a potential tool for rapidly determining lumbrokinase potency in earthworm extract intermediate.