Pharmacol. median, third quartile, and maximum. The box covers the values from the first quartile to the third quartile. Boxplot whiskers show the locations of the minimum and maximum values. Differences between distributions of molecular descriptors were assessed using the pairwise Students function implemented in Rabbit Polyclonal to MRPL47 the FSelector package. More specifically, a subset of features that were independent of each other but correlated with a class label were selected.16 Multiple regression models using the various physicochemical properties were performed and decided to not be informative (adjusted = 3 determinations at each concentration. Considering that excipients used as diluents, solubilizing brokers, and flavoring brokers are commonly used in large quantities in oral drug products, the screening concentration was 1 mM for all those sugars and 200 = 0 and = 0. Each dot represents the mean of normalized 3H-oxypurinol accumulation from three replicates in a single experiment. DISCUSSION In this report, we characterized the interactions of oral molecular excipients with the efflux transporter, BCRP. In vitro and in vivo evidence, including clinical drugCdrug interaction studies, support a role for BCRP in intestinal drug absorption.19 Of the 292 oral molecular excipients that are listed in the CERSI Excipient Browser,10 we characterized the interaction of 136 excipients with BCRP using BCRP-expressing membrane vesicles. A total of 26 excipients were deemed inhibitors of BCRP, whereas 110 were deemed noninhibitors or poor inhibitors at tested concentrations. Of the 26 inhibitors, three excipients (FD&C Red No. 40, FD&C Yellow No. 5, and FD&C Yellow No. Lapaquistat 6) had previously been shown to inhibit BCRP with IC50 values similar to our results (within 1C5-fold).9 Lapaquistat Importantly, 13 dyes and 1 flavoring agent were potent inhibitors of BCRP with IC50 values less than 5 em /em M (Table 1). The measurement of fraction unbound of BCRP-inhibiting dyes in incubation with BCRP membrane vesicles (Physique S5) showed that the majority of the dyes (17/ 22) had a fraction unbound of more than 60%, and their IC50, corrected (IC50 * fraction unbound) values were within the 95% confidence interval Lapaquistat of IC50 values (Tables S8 and ?and1).1). These IC50 values are in the range of IC50 values for established BCRP inhibitors including prescription drugs, which are considered clinically relevant BCRP inhibitors.20 For example, the IC50 value (0.5 em /em M) for elacridar against human BCRP20 is comparable to the values for FD&C Red No. 3 (0.374 em /em M), light green CF yellowish (0.943 em /em M), and D&C Red No. 28 (0.431 em /em M). To determine whether CCK8 shares a common binding site with clinical BCRP substrate drugs, we conducted mechanistic kinetic experiments with rosuvastatin and sulfasalazine. In brief, our results showed different inhibition models for the two drugs (Table S9). Clearly, excipients used in formulations of BCRP substrate drugs should be validated for their inhibitory effects on BCRP-mediated transport of that drug. Studies using in vitro systems, animal species, and humans have suggested that excipients may modulate the absorption of therapeutic brokers given orally. 21C24 In the case of inhibiting efflux transporters such as BCRP, an increase in the systemic exposure of drugs that are BCRP substrates has been noted when the drugs have been administered concomitantly with BCRP inhibitors such as curcumin and eltrombopag.25C27 Modeling and simulation tools28 have also been used to quantitatively predict the impact of excipients around the systemic exposure of the administered drug substance; this may be important for Lapaquistat drugs that are substrates of BCRP, which may include drugs in the Biopharmaceutical Classification System (BCS), Class 2, 3, and 4. For generic drugs in BCS Class 3, the results are particularly important in preparing bioequivalent formulations, since clinical studies may be waived.29 The concentration of the excipient in the gut contents and the enterocyte will ultimately determine the extent of interaction between the excipient and an efflux transporter such as BCRP. However, the work presented here may aid in the selection of excipients during formulation development for which the potential for interaction is lower when combined with a drug substance that is a BCRP substrate, therefore alleviating a.