Design optimization and pharmacokinetic study of eletriptan hydrobromide loaded solid lipid nanoparticle nasal gel targeted to brain

In the present research work, Eletriptan Hydrobromide(E-HBr)-loaded solid lipid nanoparticles (SLN’s) incorporated in a gel was prepared by emulsification solvent evaporation technique to enhance the uptake of E-HBr to brain via intra-nasal (i.n.) route and the formulations were evaluated for particle size, polydispersibility index, zeta potential, drug entrapment efficiency, in-vitro drug release, and stability of the optimized formulation. All the parameters evaluated were within the acceptable range. In-vitro drug release for the optimized gel formulation was found to be 92.45% after 12hr and was fitted to the Higuchi model with a very high correlation coefficient (R²=0.995). Pharmacokinetics studies were performed on albino male Wistar rats and the concentration of E-HBr in brain and blood plasma was measured by HPLC. The brain/blood ratio at 0.5h for E-HBr Opt.SLN’s i.n., E-HBr sol. i.n., and E-HBr sol. oral. were found to be 2.35, 1.19 and 0.80 respectively, indicating the drug transported directly from nose-to-brain, by bypassing the blood-brain barrier in the olfactory region present in the nasal cavity. The maximum concentration of drug in brain (Cmax) after i.n. administration of E-HBr-SLN gel was found to be (21465.87±1110.66ng/ml, T_max 8.45hr) significantly higher than that achieved after oral administration (6797.23±842.86ng/ml, T_max 7hr), and i.n. (16451.53±3792.40ng/ml, T_max 7.69 hr) administration of E-HBr sol. The highest drug-targeting efficiency (2.35%) and direct transport percentage (66.05%) was found with E-HBr-SLN’s as compared to the other formulations. Higher DTE (%) and DTP (%) suggest, that E-HBr-SLN gel had better brain targeting efficiency as compared to other formulations.