Ginsenoside Rg1 is a major bioactive component of ginseng. Limited information is available regarding Rg1 concentrations in the central neural system and the corresponding relationship of plasma/intracerebral concentrations, and intracerebral effects of Rg1. Awake Aβ model rats received a single subcutaneous administration of Rg1. Concentrations of unbound Rg1 and acetylcholine in the brain extracellular fluid and Rg1 in plasma were then determined. An Emax-two compartment pharmacokinetic/pharmacodynamics (PK/PD) model without effect compartment was finally obtained by evaluating three mechanism-based models. The corresponding relationship between the plasma PK and PD of Rg1 can be described as E = 119.05•C/(73.42 + C).[Formula: see text].
Keywords: Ginsenoside Rg1; PK/PD model; acetylcholine; microdialysis; pharmacokinetics.