Sun Jinzhou,Chen Qianqian,Zhuang Chumeng,Li Xiaohong,Yu Li,Jin Weifeng
Develop a novel coupled PK-PD model and apply it to quantitatively evaluate the synergistic effects of Hydroxysafflor Yellow A (HSYA) combined with Calycosin (CA) in the treatment of ischemic stroke. A total of 6 rats were modelled for middle cerebral artery occlusion (MCAO). Plasma was collected from the submandibular venous plexus of rats after the administration of HSYA and CA, and was detected and analyzed by LC-MS method. The plasma expression levels of Caspase-9, IL-1β and SOD in rats were also determined by ELISA kit. Meanwhile, a coupled PK-PD model was proposed, incorporating interaction terms between drugs and coupling of pharmacodynamic effects, to quantitatively reveal their interactions. Moreover, a numerical solution technique based on optimization methods was proposed, enabling the model to be effectively applied to experimental data. Based on the coupled PK model, HSYA and CA significantly increased each other’s metabolic rates. The model also showed that CA had a larger apparent volume of distribution and clearance in rats, while HSYA had a shorter mean retention time and elimination half-life. The coupled PK-PD model indicated a synergistic effect between HSYA and CA on all three pharmacodynamic markers, with HSYA contributing more significantly. Despite individual variability among the six rats, the parameter interpretations remained consistent. The proposed coupled PK-PD model and its numerical solution algorithm successfully revealed the synergistic effects of HSYA and CA in the treatment of ischemic stroke. This model lays the foundation for future models with more complex interactions and effects.
Wang Tianyan,Tao Ting,Liu Yi,Dong Jie,Ni Shanhong,Liu Yun,Li Yanli,Xu Ning,Sun Zengxian
Background and purposes It is unclear whether the parent Saxagliptin (SAX) in vivo is the same as that in vitro, which is twice that of 5-hydroxy Saxagliptin (5-OH SAX). This study is to construct a Pharmacokinetic-Pharmacodynamic (PK-PD) link model to evaluate the genuine relationship between the concentration of parent SAX in vivo and the effect. Methods First, we established a reliable Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS/MS) method and DPP-4 inhibition ratio determination method. Then, the T2DM rats were randomly divided into four groups, intravenous injection of 5-OH SAX (0.5 mg/kg) and saline group, intragastric administration of SAX (10 mg/kg) and Sodium carboxymethyl cellulose (CMC-Na) group. Plasma samples were collected at different time points for subsequent testing. Finally, we used the measured concentrations and inhibition ratios to construct a PK-PD link model for 5-OH SAX and parent SAX. Results A two-compartment with additive model showed the pharmacokinetic process of SAX and 5-OH SAX, the concentration-effect relationship was represented by a sigmoidal E max model and sigmoidal E max with E 0 model for SAX and 5-OH SAX, respectively. Fitting parameters showed SAX was rapidly absorbed after administration ( T max =0.11 h, t 1/2, ka =0.07 h), widely distributed in the body (V ≈ 20 L/kg), plasma exposure reached 3282.06 ng*h/mL, and the elimination half-life was 6.13 h. The maximum plasma dipeptidyl peptidase IV (DPP-4) inhibition ratio of parent SAX was 71.47%. According to the final fitting parameter EC 50 , EC 50, 5−OH SAX =0.46EC 50, SAX(parent) , it was believed that the inhibitory effect of 5-OH SAX was about half of the parent SAX, which is consistent with the literature. Conclusions The PK-PD link model of the parent SAX established in this study can predict its pharmacokinetic process in T2DM rats and the strength of the inhibitory effect of DPP-4 based on non-clinical data.
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