Interactions between human multidrug resistance related protein (MRP2; ABCC2) and excipients commonly used in self-emulsifying drug delivery systems (SEDDS).

The aim of this study was to investigate the multidrug resistance related protein-2 (MRP2) inhibition effect of excipients commonly employed in the formulation of self-emulsifying drug delivery systems (SEDDS). Cytotoxicity and safe dosages of fifteen excipients, including five surfactants, three oils, three co-surfactants and four solid carriers, were compared using MTT assay. Caco-2 cell permeability and MRP2 vesicles transport assays were used in the inhibition analysis. Scutellarin was shown to be a substrate of MRP2 and used as a probe in the inhibition assay. Twelve excipients decreased efflux ratio of scutellarin in Caco-2 model, among them six excipients showed inhibition effect on MRP2 in MRP2 transport model. In Caco-2 model, Cremophor EL, Maisine 35-1, PEG 2000 and β-cyclodextrin reduced efflux ratio of scutellarin the most in the four different excipients groups. The efflux reduction mechanism was further validated by MRP2 transport assay in inhibiting MRP2 activity in Cremophor EL and PEG 2000. It is suggested that scutellarin quantified by LC-MS can be used as a model drug for MRP2 inhibition analysis using Caco-2 permeability and vesicles transport analyses. Together they constitute a sensitive and rapid screening method for assessing interactions between excipients and MRP2 in SEDDS formulation.