To explore the potential of "physical property model" based on the concept of quality by design(QbD),during the application of process analysis technology(PAT) in the concentration process. The Carthami Flos was used as a model drug. Firstly, the total flavonoid retention rate and the hydroxysafflor yellow A(HSYA) retention rate of the concentrated solution were used as indicators to determine the concentration temperature range of the Carthami Flos extract. Then different concentrations were prepared at the optimal concentration temperature, and the corresponding viscosity(η) and electrical conductivity(σ) at different concentrations and temperatures were measured. Data processing software such as Excel, 1 stOpt, SPSS, and MATLAB were used to establish Carthami Flos extract's mathematical model of physical parameters: ρ-C, η-C, η-T, η-C-T, σ-T, σ-C-T. The results showed that the best concentration temperature of the Carthami Flos extract should not exceed 60 ℃, and the R~2 of the exponential equation and Arrhenius equation established based on physical parameters was all greater than 0.9, indicating that such model had better predictive ability. The mathematical model:η=14.465 1 exp(-0.019 8T+ 0.771 1C-0.058 3C~2), σ=4.061 0 + 0.004 3T +(-1.104 1 +0.950 9T)C-0.556 9TC~2 can be used to reflect the comprehensive effect of concentration and temperature on viscosity or conductance, laying foundation for the establishment of an online monitoring system for the viscosity or conductivity of the extraction liquid in the concentration step, rapid prediction of the concentration status, and control of the concentration endpoint. This study has initially proved the feasibility of using the physical property model as the core of the research idea in application of PAT for intelligent quality control of traditional Chinese medicine concentration links, providing a reference for the online intelligent monitoring of concentration steps of traditional Chinese medicine extracts.
Keywords: concentrate; extract; mathematical model; physical parameters; process analytical technology; quality by design(QbD).