Evaluation of the permeability and P‐glycoprotein efflux of carbamazepine and several derivatives across mouse small intestine by the Ussing chamber technique

Abstract

SUMMARYPurpose: The rational discovery and development of new antiepileptic drugs (AEDs) with safer therapeutic index and better pharmacokinetic properties is still warranted nowadays. Because the long-term management of epilepsy is attained by means of orally administered AEDs, investigation of their potential to be well absorbed at the intestinal level is mandatory. Moreover, involvement of the efflux transport mediated by P-glycoprotein (P-gp) may compromise the systemic and central nervous system disposition of AEDs. Therefore, this study aimed at characterizing mouse jejunal passive transport and the possible active efflux mediated by P-gp of a series of dibenz, carbamazepine-10, 11-epoxide[CBZ-E],10,11-trans-dihydroxy-10,11-dihydrocarbamazepine [trans-diol], and BIA 2-024), which comprise some AEDs and metabolites. Methods: Permeation studies were performed with freshly excised mouse jejunum segments mounted in Ussing chambers. Absorptive (M-S) and secretive (S-M) transports were analyzed with and without verapamil, which is a P-gp inhibitor widely recognized. Apparent permeability coefficients (P app ) in both directions and in absence or presence of verapamil were determined for each test compound. The in vitro method was validated using five controls that included high and low permeable markers with known absorption fraction (Fa) and also well-known P-gp substrates. The integrity of intestinal membrane was guaranteed during the assay by measuring the transepithelial electrical resistance. Key Findings: The correlation obtained between P app (M-S) and Fa of references was high (r 2 = 0.9945), and could be used to classify the derivatives according to Biopharmaceutical Classification System: CBZ and OXC were the only classified as highly permeable. The P app (S-M) of OXC, CBZ-E, R-Lic, and BIA 2-024 were significantly higher than their P app (M-S). After verapamil addition, their P app (S-M) lowered while P app (S-M) increased, suggesting the involvement of P-gp on the transport of those compounds across mouse jejunum segments. In opposition, CBZ, S-Lic, and trans-diol presented no statistical differences between the P app values reported in both directions, with or without verapamil. The results reported herein suggest that differences in biodisposition of S-Lic and R-Lic might result from their distinct interaction with P-gp. Significance: The Ussing chamber model used herein showed to be useful for predicting Fa of AEDs and the involvement of efflux transport, namely P-gp, on their absorption. This is an important achievement as compounds that are not transported by P-gp may offer advantages when used in patients with pharmacoresistant epilepsy.

Effects of dietary essential oil and enzyme supplementation on growth performance and gut health of broilers challenged by Clostridium perfringens

“…Mucosal atrophy could result in greater epithelial permeability and impair barrier function, and lead to bacterial translocation and subsequent sepsis (Sun et al, 2006). The increased propranolol permeability and decreased Rho123 permeability, which indicated increased passive transcellular transport and decreased P-gp dependent efflux transport (Fortuna et al, 2012), suggested that the intestinal membrane viability was decreased and P-gp function was impaired. Moreover, increased plasma endotoxin levels were observed when chicks fed with basal diet were challenged with C. perfringens, which might result from overgrowth of gram-negative bacteria (particularly E. coli), and bacteria and endotoxin translocation into organs and blood circulation (Collier et al, 2008;Liu et al, 2010Liu et al, , 2012.…”

“…The passive transcellular transport marker and P-glycoprotein (P-gp) dependent efflux transport marker (propranolol and Rhodamine 123 (Rho123), respectively) were assessed to investigate intestinal membrane viability and P-gp transporter functionality (Fortuna et al, 2012). Propranolol permeability was investigated in mucosal to serosal direction (M-S), while Rho123 was assessed from serosa to mucosa (S-M).…”

Consequences of Mrp2 deficiency for diclofenac toxicity in the rat intestine ex vivo

“…The Ussing Chamber protocol was adapted from a published method (Oga et al, 2013;Fortuna et al, 2012). Rats were sacrificed by cervical dislocation and the entire small intestine was rapidly removed, stored in the Krebs-Ringer buffer (KRB) solution, composed of 115 mM NaCl, 25 mM NaHCO 3 , 2.4 mM K 2 HPO 4 , 1.2 mM CaCl 2 , 1.2 mM MgCl 2 , 0.4 mM KH 2 PO 4 , and 10 mM D-glucose, pH7.4 saturated with carbogen (95% O 2 , 5% CO 2 ).…”

Prospective Randomized Controlled Trial of Nimodipine as Add-On Therapy in the Treatment of Focal Refractory Epilepsy Patients: A Pilot Study

“…Calcium channel blockers are being used to reduce that drug efflux by interference with P-gp function in intestinal wall and in the apical membrane of brain capillary endothelial cells of the blood-brain barrier [11]. The most commonly calcium antagonist used to block the P-gp protein is Verapamil [14].…”

“…In the last years, there is increasing evidence that drug efflux transporters (namely P-gp protein [P-glycoprotein] and MDRP [multidrug resistant protein] may play a role in drug-resistant epilepsy by limiting gastrointestinal absorption and brain access of antiepileptic drugs [7][8][9][10][11][12][13].…”