Drug Transport across Porcine Intestine Using an Ussing Chamber System: Regional Differences and the Effect of P-Glycoprotein and CYP3A4 Activity on Drug Absorption

Abstract

Drug absorption across viable porcine intestines was investigated using an Ussing chamber system. The apparent permeability coefficients, Papp,pig, were compared to the permeability coefficients determined in humans in vivo, Peff,human. Eleven drugs from the different Biopharmaceutical Classification System (BCS) categories absorbed by passive diffusion with published Peff,human values were used to test the system. The initial experiments measured Papp,pig for each drug after application in a Krebs–Bicarbonate Ringer (KBR) buffer and in biorelevant media FaSSIF V2 and FeSSIF V2, mimicking fasted and fed states. Strong sigmoidal correlations were observed between Peff,human and Papp,pig. Differences in the segmental Papp,pig of antipyrine, cimetidine and metoprolol confirmed the discrimination between drug uptake in the duodenum, jejunum and ileum (and colon); the results were in good agreement with human data in vivo. The presence of the P-gp inhibitor verapamil significantly increased Papp,pig across the ileum of the P-gp substrates cimetidine and ranitidine (p < 0.05). Clotrimazole, a potent CYP3A4 inhibitor, significantly increased Papp,pig of the CYP3A4 substrates midazolam, verapamil and tamoxifen and significantly decreased the formation of their main metabolites. In conclusion, the results showed that this is a robust technique to predict passive drug permeability under fasted and fed states, to identify regional differences in drug permeability and to demonstrate the activity of P-gp and CYP3A4.

Using Ex Vivo Porcine Jejunum to Identify Membrane Transporter Substrates: A Screening Tool for Early—Stage Drug Development

“…Therefore, further studies have to be performed to clarify their function. P eff,human (30 × 10 −6 cm/s) was around 80 times greater [ 96 ]; however, as mentioned in previous work, this difference is based on the different considerations of the surface areas [ 45 , 97 ]. In the presence of the P-gp inhibitor verapamil, P app,pig in the jejunum increased 4-fold to 1.64 ± 0.79 × 10 −6 cm/s ( Figure 2 a).…”

“…P-gp is a transporter of high clinical relevance, and considerable information regarding its structure, DDI and drug resistance is available in the literature [89][90][91][92]. The activity and successful inhibition of P-gp in porcine intestine were already demonstrated in our previous work [45]. For two substrates, ranitidine (K m = 0.27 mM, [93]) and cimetidine, P-gp inhibition resulted in a significant increase of P app,pig in the ileum, but not in the jejunum.…”

“…To date, little work has been done to study intestinal drug permeation using porcine intestine [36][37][38][39][40][41][42][43][44]. We recently demonstrated that apparent permeability coefficients P app,pig measured using ex vivo porcine intestine in an Ussing chamber set-up showed a good correlation to effective permeability coefficients P eff,human reported in humans in vivo [45]. In addition to comparing passive transport results with those from human intestine, the study also demonstrated that P450 3A4 and P-gp activities were retained, confirming the viability of the tissue.…”

Comparative Study of Protective Effect of Cimetidine and Verapamil on Paracetamol-Induced Hepatotoxicity in Mice

“…Cimetidine is one of the enzyme inducer drugs i.e., it decreases the activity of the cytochromal enzymes [9]. Cimetidine has the property of inhibiting the cytochromal enzyme CYP3A4 [10], enzyme CYP2D6 [11], and enzyme CYP1A2 [12]. Toxic metabolite are produced as a result of metabolism of paracetamol by the cytochromal enzymes is inhibited by cimetidine.…”

Evaluation of human primary intestinal monolayers for drug metabolizing capabilities

“…Thus, these model systems frequently fail to recapitulate many features of the human small intestine with respect to dug metabolism, efficacy, uptake, bioavailability and toxicity. Ex vivo models utilize intact sections of intestinal tissue, often placed into perfusion systems but again are generally limited to non-human tissue [15–17]. However, both the luminal and basal environment of the small intestine is readily accessed in these models and regional intestinal differences can be studied.…”