PLGA Nanoparticles for Nose to Brain Delivery of Clonazepam: Formulation, Optimization by 32 Factorial Design, In Vitro and In Vivo Evaluation

Background: Intranasal administration of biodegradable nanoparticles has been extensively studied for targeting the drug directly to CNS through the olfactory or trigeminal route bypassing the blood brain barrier. Objective: The objective of the present study was to optimize Clonazepam loaded PLGA nanoparticles (CLO-PNPs) by investigating the effect of process variables on the responses using 32full factorial design. Methods: Effect of two independent factors-amount of PLGA and concentration of Poloxamer 188, were studied at low, medium, and high levels on three dependent responses-%Entrapment efficiency, Particle size (nm), and % cumulative drug release at 24hr. Results: %EE, Particle size, and %CDR at 24hr of the optimized batch was 63.7%, 165.1 nm, and 86.96%, respectively. Nanoparticles were radiolabeled with 99mTc and biodistribution was investigated in BALB/c mice after intranasal and intravenous administrations. Significantly higher brain/blood uptake ratios and AUC values in the brain following intranasal administration of CLO-PNPs indicated more effective brain targeting of CLO. Higher brain uptake of intranasal CLO-PNPs was confirmed by rabbit brain scintigraphy imaging. A histopathological study performed on goat nasal mucosa revealed no adverse response of nanoparticles. TEM image exhibited spherical shaped particles in the nano range. DSC and XRD studies suggested Clonazepam encapsulation within the PLGA matrix. The onset of occurrence of PTZ-induced seizures in rats was significantly delayed by intranasal nanoparticles as compared to intranasal and intravenous CLO-SOL. Conclusion: This investigation exhibits rapid rate and higher extent of CLO transport in the brain with intranasal CLO-PNPs suggesting a better option as compared to oral and parenteral route in the management of acute status epilepticus.