Influence of administration vehicles and drug formulations on the pharmacokinetic profile of lamotrigine in rats

• Autor(a) principal: Castel-Branco, M. M.
• Data de Publicação: 2002
• Outros Autores: Figueiredo, I. V., Falcão, A. C., Macedo, T. R. A., Caramona, M. M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/101110; https://doi.org/10.1046/j.1472-8206.2002.00096.x
• topic: drug formulation; lamotrigine; pharmacokinetic profile; rat; vehicle administration

Given that administration vehicles and drug formulations can affect drug bioavailability, their influence on the pharmacokinetic profile of lamotrigine (LTG), a newgeneration anti-epileptic drug, was studied in rats. Three different formulations administered intraperitoneally at a dose of 10 mg⁄kg were used: (1) LTG suspended in a 0.25% methylcelulose solution, (2) LTG dissolved in a 50% propylene glycol solution, and (3) LTG isethionate dissolved in distilled water. Plasma and brain homogenate levels were determined in order to evaluate vehicle-dependent drug absorption. The results demonstrated rapid absorption of LTG when it was administered as an aqueous solution, in contrast to a slower and more erratic absorption after the injection of either the lipophilic solution or the suspension. A plasma peak was achieved 15 min post-dose with the aqueous solution, with a brain peak being achieved 15 min later, while with the other formulations both plasma and brain homogenate peaks were reached 2 h after LTG administration. This study suggests that LTG isethionate dissolved in distilled water is the most suitable formulation for successful LTG pharmacokinetic studies in rats.