Influência da epilepsia na farmacocinética do enalapril e da carbamazepina em ratos

Abstract

Epilepsy is a set of neurological conditions that have in common that the occurrence of recurrent seizures. The Temporal Lobe Epilepsy (TLE) is the most common cause of seizures resistant to drugs. Some of the animal models used in the literature to study the epileptic condition are genetically susceptible strains of animals with epilepsy, such as WAR rats (Wistar audiogenic Rats). Carbamazepine is one of the most commonly prescribed antiepileptic drugs also used in psychiatric disorders. Due to the low therapeutic index, this drug is prone to significant drug interactions, and small changes in plasma concentrations may result in loss of efficacy or signs of intoxication. Furthermore, it may be an inducer of various liver enzymes. Angiotensin II peptide formed from AngI cleavage by angiotensin converting enzyme, has been considered as the main active peptide of the renin-angiotensin system (RAS) may be considered as a neurotransmitter/neuromodulator through its action on AT1 and AT2 receptors present in various brain regions. Enalapril is an angiotensin converting enzyme inhibitor, and is one of the most used drugs for treating hypertension in patients with epilepsy. This study aimed to evaluate the influence of epileptic seizures induced in experimental epilepsy, on the pharmacokinetics of enalapril and carbamazepine, a known anticonvulsant, when used alone or in combination. For this, we developed methodology to quantify the enalapril and carbamazepine simultaneously in rat plasma and perform evaluation of kinetic disposition of these drugs in rats Wistar and WAR (not subject to the kindling). Enalapril and carbamazepine were analyzed in the plasma by liquid chromatography Ultra-Performance coupled to a mass spectrometer. The sample preparation was done by liquid-liquid extraction. The method was developed and validated according to current legislation (ANVISA RDC 27/2012) and is suitable for use in pharmacokinetic studies. It was found that the pharmacokinetic studies carbamazepine only had their parameters modified WAR when administered to rats in combination with enalapril, with decreased bioavailability of the drug (AUC 0-∞: 9395 vs. 35796 ng · hr / mL, CWA and CCA respectively). With respect to enalapril, the genetic background for epilepsy increased bioavailability the drug compared to its control (AUC 0-∞: 105.25 vs. 273,05ng.h / ml, ECA and EWA, respectively), moreover, the association with carbamazepine reduced the plasma concentrations of enalapril in both control groups, as in WAR groups.