RESUMO
The aim of the present investigation was to prepare and characterize clobazam mucoadhesive microemulsion (CZMME) to assess brain drug uptake and protection against pentylenetetrazole (PTZ)-induced convulsions in mice. Clobazam microemulsion (CZME) and CZMME were prepared by titration method and characterized. Brain uptake and pharmacokinetic parameters were calculated from drug concentration in mice brain versus time plots following intranasal administration of radiolabeled CZME and CZMME, intravenous and intranasal administration of radiolabeled clobazam solution. Gamma scintigraphy imaging of rabbit brain following intranasal administration was performed. Formulations were investigated for the onset of seizures in PTZ-challenged mice. Brain targeting efficiency and direct nose-to-brain transport percentage for mucoadhesive microemulsion suggested an improved brain uptake following intranasal administration. The findings were supported by gamma scintigraphy images. Delay in onset of PTZ-induced seizures with CZMME compared with positive control and placebo-treated groups confirmed the improved brain uptake. However, extensive animal studies followed by clinical trials are necessary to develop a product suitable for emergencies of acute seizures in status epilepticus and patients suffering from drug tolerance and hepatic impairment on long-term use in treatment of epilepsy, schizophrenia, and anxiety.
