Human BCRP Vesicle Kit (HEK293-derived)

Is BCRP assessment required by FDA and EMA for drug approval submissions?

Yes. BCRP (ABCG2) is one of the transporters for which the FDA Drug Interaction Guidance (2017) and EMA Guideline on the Investigation of Drug Interactions (2013) require in vitro assessment as part of the standard DDI submission package. Both agencies recommend the vesicular transport assay using BCRP-overexpressing inside-out membrane vesicles as the primary method to determine whether a new molecular entity is a BCRP substrate or inhibitor. Positive substrate or inhibitor findings trigger further clinical DDI study recommendations based on R-value calculations.

What does the guaranteed ATP/AMP ratio >10 mean, and why is it important?

The ATP/AMP ratio in a vesicular transport assay measures the ratio of ATP-dependent transport (in the presence of ATP) to ADP-stimulated transport (in the presence of AMP). A ratio >10 for a validated BCRP probe substrate (typically estrone-3-sulfate) confirms that the vesicles are functionally active and capable of ATP-driven efflux transport. This is a quality control benchmark that demonstrates the vesicle preparation is suitable for regulatory-grade assay work. Without a confirmed ATP/AMP ratio, transport data cannot be reliably interpreted or submitted in DDI dossiers.

Which probe substrates and inhibitors are recommended for BCRP vesicular transport assays?

The most commonly used probe substrate for BCRP vesicular transport assays is estrone-3-sulfate (E1S), which is well-characterised, commercially available in radiolabelled form (³H-E1S), and cited in both FDA and EMA guidance. Methotrexate and prazosin are also used as alternative substrates. For positive inhibitor controls, Ko143 and fumitremorgin C (FTC) are the reference BCRP inhibitors. Elacridar (GF120918) is used when dual P-gp/BCRP inhibition is relevant. The Cell4Pharma kit is compatible with all standard probe substrates and detection methods (radiolabel, fluorescent, LC-MS/MS).

Can the BCRP vesicle kit be used together with other ABC transporter kits in a multi-transporter DDI panel?

Yes — this is the standard practice in drug development. Regulatory agencies expect a complete transporter DDI package, and BCRP is typically assessed in parallel with P-gp (ABCB1) and BSEP (ABCB11), with MRP2 (ABCC2) added where hepatic efflux is clinically relevant. Cell4Pharma offers a full range of ABC transporter vesicle kits (P-gp, BSEP, MRP1, MRP2, MRP5, BCRP) that share a common assay format and buffer system, enabling parallel processing within the same experiment. The Human Control Vesicle Kit (C4PVK009) serves as the negative control across all transporter vesicle assays in the panel.

What is the recommended negative control for the BCRP vesicular transport assay?

The Human Control Vesicle Kit (C4PVK009) from Cell4Pharma is the recommended negative control. Control vesicles are prepared from HEK293 cells under the same conditions as the BCRP-overexpressing vesicles but without transporter transfection — enabling direct comparison of ATP-dependent transport in the presence and absence of BCRP. Using matched control vesicles is required to confirm BCRP-specific transport and to correct for non-specific binding and passive uptake into the vesicle preparation. Both the BCRP and Control Vesicle Kits are available via SeamlessBio for the DACH region.