In Vitro Evaluation of Absorption Characteristics of Peramivir for Oral Delivery

Background and Objective Peramivir is a novel antiviral agent approved for the treatment of severe influenza. However, the development of oral formulation of peramivir has been severely hurdled by poor bioavailability (human, ≤3%). The present work aims to evaluate oral permeability characteristics of peramivir. Methods In vitro gastrointestinal stability, metabolic stability in human intestinal S9 fraction and Caco-2 permeability were performed. The liquid chromatography with tandem mass spectrometric (LC–MS/MS) was used to quantify peramivir in buffer and biological sample. Using GastroPlus™ software, intestinal effective permeability coefficient ( P eff ) of peramivir was estimated. Results Our results indicated that peramivir maintained stability in pH 5.5 and 7.4 buffers, fasted state simulated gastric fluid and fasted state simulated intestinal fluid, and human intestinal S9 fractions. The apparent permeability coefficient ( P app ) values of peramivir (10 μM) were 3.29 ± 0.73 × 10 −7 cm/s in a Caco-2 cell model. In vivo intestinal effective permeability coefficient ( P eff ) was estimated to be 0.06 × 10 −4 cm/s. Furthermore, co-incubating with cyclosporine, mitoxantrone, rifampicin, or paroxetine, the apical (AP) to basolateral (BL) flux of peramivir decreased ( p < 0.05). The efflux and influx of peramivir was not significantly affected with co-incubation with verapamil, MK-571, or diclofenac ( p > 0.05). Conclusions These results revealed that carrier-mediated transports, including OATP1B (organic anion transport 1B) and OCT1 (organic cation transport 1), might be involved in the absorption of peramivir. In conclusion, our results provide insight into the poor oral bioavailability of peramivir. Peramivir can be classified as a BCS-III (high solubility/low permeability) and BDDCS-III high solubility/poor metabolism) drug. The oral bioavailability of peramivir primarily depends on its permeability across cell membranes. Both of passive and active transports are involved in the permeability of peramivir.