Nose-to-brain delivery of paliperidone palmitate poloxamer-guar gum nanogel: Formulation, optimization and pharmacological studies in rats

Oral delivery of paliperidone palmitate (PPD), a potent antipsychotic agent, has been reported with a potential risk of very serious drug-induced adverse events such as tachycardia, hyperprolactinemia, sexual dysfunction, and neutropenia. Alternatively, the potential of nasal delivery has also been explored to treat CNS complications by delivering the medicines directly to the brain bypassing the blood-brain barrier. Hence, the objectives of current work were to formulate, design, optimize, and investigate the therapeutic potency of PPD-loaded intranasal in-situ gel (PPGISG) in the treatment of schizophrenia. PPD-nanoemulsion (PNE) was fabricated using water titration technique, was further optimized via Box-Behnken design. Furthermore, the optimized PNE was evaluated for parameters such as globule size, polydispersity index, zeta potential, and % entrapment efficiency were found to be 21.44±1.58nm, 0.268±0.02, -25.56±1.6mV, and 99.89±0.25%, respectively. PNE was further converted to PPGISG utilizing two polymers, poloxamer, and guar gum. Simultaneously, ex-vivo permeation for PNE, PPGISG, and PPD-suspension was found to be 211.40±4.8, 297.89±3.9 and 98.66±1.6μg/cm², respectively. While PPGISG nanoparticles showed 1.58 and 5.65-folds more J_ss than PNE and PPD-suspension. Behavioral studies confirmed that no extrapyramidal symptoms were observed in experimental animals post intranasal administration. Finally, the outcomes of the in-vivo hemato-compatibility study proved that intranasal formulation did not cause any alteration in leukocytes, RBCs, and neutrophils count. Therefore, intranasal delivery of PPGISG can be considered a novel tool for the safe delivery of PPD in schizophrenic patients.