The BioGIT System: a Valuable In Vitro Tool to Assess the Impact of Dose and Formulation on Early Exposure to Low Solubility Drugs After Oral Administration

The purpose of this study was to evaluate the usefulness of the in vitro biorelevant gastrointestinal transfer (BioGIT) system in assessing the impact of dose and formulation on early exposure by comparing in vitro data with previously collected human plasma data of low solubility active pharmaceutical ingredients. Eight model active pharmaceutical ingredients were tested; Lu 35-138C (salt of weak base in a HP-beta-CD solution, three doses), fenofibrate (solid dispersion, tablet, two doses), AZD2207 EQ (salt of weak base, capsule, three doses), posaconazole (Noxafil® suspension, two doses), SB705498 (weak base, tablets vs. capsules), cyclosporine A (Sandimmun® vs. Sandimmun® Neoral), nifedipine (Adalat® capsule vs. Macorel® tablet), and itraconazole (Sporanox® capsule vs. Sporanox® solution). AUC_0–0.75h values were calculated from the apparent concentration versus time data in the duodenal compartment of the BioGIT system. Differences in AUC_0–0.75h values were evaluated versus differences in AUC_0–1h and in AUC_0–2h values calculated from previously collected plasma data in healthy adults. Ratios of mean AUC_0–0.75h, mean AUC_0–1h, and mean AUC_0–2h values were estimated using the lowest dose or the formulation with the lower AUC_0–0.75h value as denominator. The BioGIT system qualitatively identified the impact of dose and of formulation on early exposure in all cases. Log-transformed mean BioGIT AUC_0–0.75h ratios correlated significantly with log-transformed mean plasma AUC_0–1h ratios. Based on this correlation, BioGIT AUC_0–0.75h ratios between 0.3 and 10 directly reflect corresponding plasma AUC_0–1h ratios. BioGIT system is a valuable tool for the assessment of the impact of dose and formulation on early exposure to low solubility drugs.