Phospholipid complex as an approach for bioavailability enhancement of echinacoside

Abstract

Context: Echinacoside (ECH) has been shown to possess a multitude of pharmacological activities, however, oral administered ECH failed to fulfill its therapeutic potential due to poor absorption and low bioavailability. Thus, there is a pressing need to develop a new oral dosage form to enhance its intestinal absorption and improve bioavailability.Objective: The aim of this study was to formulate ECH into phospholipid complex (phytosome, PHY) to enhance intestinal absorption and oral bioavailability of ECH in vivo.Methods: The PHY was prepared by a solvent evaporation method and was characterized by differential scanning calorimetry (DSC) and infrared spectroscopy (IR), and then the physicochemical properties, intestinal absorption and bioavailability of the PHY were investigated.Results: Compared with the physical mixture (MIX) or ECH alone, the n-octanol/water partition coefficient (P) determination results showed that the lipophilicity of ECH was significantly enhanced by formation of PHY. Accordingly, the intestinal absorption rate (Ka) was improved to 2.82-fold and the effective permeability coefficient (Peff) increased to 3.39-fold. The concentrations of ECH in rat plasma at different times after oral administration of PHY were determined by HPLC. Pharmacokinetic parameters of the PHY in rats were Tmax = 1.500 h, Cmax = 3.170 mg/mL, AUC0–∞ = 9.375 mg/L h and AUC0–24 = 7.712 mg/L h, respectively.Conclusions: Compared with ECH alone or the MIX group, the relative bioavailability of ECH was increased significantly after formulation into PHY (p < 0.05). This might be mainly due to an improvement of the absorption of PHY.