Intranasal delivery of topiramate nanoemulsion: Pharmacodynamic, pharmacokinetic and brain uptake studies

Epilepsy is the noncommunicable and chronic central nervous system disorder characterized by frequent, unprovoked seizures, or electrical disturbances in the brain. Topiramate is used as an antiepileptic drug for the treatment of partial onset seizures, generalized seizures and Lennox-Gastaut Syndrome. Topiramate, a BCS class II drug, has a relatively low bioavailability. It is also a substrate of P-glycoprotein and Blood Brain Barrier restricts its entry into the brain. This investigation was aimed to prepare O/W nanoemulsion delivery system of topiramate to improve its brain bioavailability. Topiramate loaded nanoemulsion was prepared by phase titration method. It was consisting of 2% w/w Capmul MCM C8, 32% w/w Tween 20:Carbitol (2:1) and 66% w/w water. It was characterized for globule size, viscosity, polydispersibility index, zeta potential, pH, conductivity values, transmittance and TEM. Pharmacodynamic, pharmacokinetic and brain drug uptake study was carried out using wistar albino rats post intranasal and oral administration. Topiramate loaded nanoemulsion was having a globule size of 4.73 ± 0.52 nm. It was stable for six months. Brain uptake of topiramate post intranasal administration of topiramate loaded nanoemulsion was significantly (P < 1.86 × 10^-8) higher when it was compared with oral administration of topiramate loaded nanoemulsion. This study indicates that intranasal administration of topiramate containing nanoemulsion could be an encouraging approach for the treatment of epilepsy to minimize the dose of topiramate in direction to avoid dose related adverse events.