Application of Method Suitability for Drug Permeability Classification

Experimental models of permeability in animals, excised tissues, cell monolayers, and artificial membranes are important during drug discovery and development as permeability is one of several factors affecting the intestinal absorption of oral drug products. The utility of these models is demonstrated by their ability to predict a drug’s in vivo intestinal absorption. Within the various permeability models, there are differences in the performance of the assays, along with variability in animal species, tissue sources, and cell types, resulting in a variety of experimental permeability values for the same drug among laboratories. This has led to a need for assay standardization within laboratories to ensure applicability in the drug development process. Method suitability provides a generalized approach to standardize and validate a permeability model within a laboratory. First, assay methodology is optimized and validated for its various experimental parameters along with acceptance criteria for the assay. Second, the suitability of the model is demonstrated by a rank order relationship between experimental permeability values and human extent of absorption of known model compounds. Lastly, standard compounds are employed to classify a test drug’s intestinal permeability and ensure assay reproducibility and quality. This review will provide examples of the different aspects method suitability for in situ (intestinal perfusions), ex vivo (everted intestinal sacs, diffusion chambers), and in vitro (cell monolayers, artificial membranes) experimental permeability models. Through assay standardization, reference standards, and acceptance criteria, method suitability assures the dependability of experimental data to predict a drug’s intestinal permeability during discovery, development, and regulatory application

CriticalSorb promotes permeation of flux markers across isolated rat intestinal mucosae and Caco-2 monolayers

Purpose CriticalSorb™ is a novel absorption enhancer based on Solutol® HS15, one that has been found to enhance the nasal transport. It is in clinical trials for nasal delivery of human growth hormone. The hypothesis was that permeating enhancement effects of the Solutol®HS15 component would translate to the intestine. Methods Rat colonic mucosae were mounted in Ussing chambers and Papp values of [14C]-mannitol, [14C]-antipyrine, FITC-dextran 4000 (FD-4), and TEER values were calculated in the presence of CriticalSorb™. Tissues were fixed for H & E staining. Caco-2 monolayers were grown on Transwells™ for similar experiments. Results CriticalSorb™(0.01% v/v) significantly increased the Papp of [14C]-mannitol, FD-4 [14C]-antipyrine across ileal and colonic mucosae, accompanied by a decrease in TEER. In Caco-2 monolayers, it also increased the Papp of [14C]-mannitol FD-4 and [14C]-antipyrine over 120 min. In both monolayers and tissues, it acted as a moderately effective P-glycoprotein inhibitor. There was no evidence of cytotoxicity in Caco-2 at concentrations of 0.01% for up to 24 h and histology of tissues showed intact epithelia at 120 min. Conclusions Solutol® HS15 is the key component in CriticalSorb™ that enables non-cytotoxic in vitro intestinal permeation and its mechanism of action is a combination of increased paracellular and transcellular flux.R10809 SFI Cluster IDDNSB. 13/6/201