An auxiliary strategy of partial least squares regression in pharmacokinetic/pharmacodynamic studies: A case of application of guhong injection in myocardial ischemia/reperfusion rats.

Guhong injection (GHI) has been applied in the therapy of cardio-cerebrovascular disease in clinic, but there is no report about the pharmacokinetic/pharmacodynamic (PK/PD) research on GHI treating myocardial ischemia/reperfusion (MI/R) injury in rats. In this study, eight compounds of GHI in plasma, including N-acetyl-L-glutamine (NAG), chlorogenic acid (CGA), hydroxysafflor yellow A (HSYA), p-coumaric acid ( pCA), rutin, hyperoside, kaempferol-3-O-rutinoside, and kaempferol-3-O-glucoside, were quantified by LC-MS/MS. We discovered that the values of t_1/2β, k₁₂, V₂, and CL₂ were larger than those of t_1/2α, k₂₁, V₁, and CL₁ for all compounds. The levels of four biomarkers, creatine kinase-MB (CK-MB), cardiac troponin I (cTn I), ischemia-modified albumin (IMA), and alpha-hydroxybutyrate dehydrogenase (α-HBDH) in plasma were determined by ELISA. The elevated level of these biomarkers induced by MI/R was declined to different degrees via administrating GHI and verapamil hydrochloride (positive control). The weighted regression coefficients of NAG, HSYA, CGA, and pCA in PLSR equations generated from The Unscrambler X software (version 11) were mostly minus, suggesting these four ingredients were positively correlated to the diminution of the level of four biomarkers. E_max and ED₅₀, two parameters in PK/PD equations that were obtained by adopting Drug and Statistics software (version 3.2.6), were almost enlarged with the rise of GHI dosage. Obviously, all analytes were dominantly distributed and eliminated in the peripheral compartment with features of rapid distribution and slow elimination. With the enhancement of GHI dosage, the ingredients only filled in the central compartment if the peripheral compartment was replete. Meanwhile, high-dose of GHI generated the optimum intrinsic activity, but the affinity of compounds with receptors was the worst, which may be caused by the saturation of receptors. Among the eight analytes, NAG, HSYA, CGA, and pCA exhibited superior cardioprotection, which probably served as the pharmacodynamic substance basis of GHI in treating MI/R injury.