Abstract: 
The aim of this study was to formulate the microemulsion (ME) for nasal delivery of BCS Class-II drug Modafinil, used for the treatment of narcolepsy and attention deficit hyperactivity disorder (ADHD) optimized by ‘D-Optimal Mixture design’ and evaluation of its in-vitro and ex-vivo potential. Modafinil loaded mucoadhesive microemulsion (MME) was prepared with chitosan and concentration of chitosan was optimized by evaluating its stability after dilution, particle size and percentage transmittance. D-optimal mixture experimental design was applied to optimize microemulsion. The optimized batch revealed smaller droplet size (< 100nm), maximum % transmittance (>95% for 100 times diluted formulation) and was studied for stability for 3 months. The potential of chitosan loaded ME was compared to drug loaded ME system with a view to Permeation Coefficient and Diffusion Coefficient. The rate and extent of % drug diffusion was studied by using dialysis sac method, shows drug suspension had less release (39.658±0.964 %) as compared to drug loaded ME (53.6413±1.06 %) and MME (69.618±1.035 %) formulations in 4 hr. Ex-vivo study was performed using isolated tissue of the sheep nasal mucosa, approximately 50% drug released within 4 hrs, 2 hrs and 1.5hrs from drug suspension, drug loaded ME and MME respectively. The significant difference (p<0.05) was observed for in vitro and ex vivo drug release between ME, MME and drug suspension. Therefore MME can be used as a possible alternative dosage form of Modafinil to improve its therapeutic potential.

Keywords: Modafinil, Microemulsion, Mucoadhesive, Intranasal.