Nasal in-situ gels for delivery of rasagiline mesylate: improvement in bioavailability and brain localization.

Intranasal thermosensitive gel for rasagiline mesylate (RM) was developed for effective treatment of Parkinson's disease. Intranasal gels were prepared by combination of poloxamer 407 and poloxamer 188 (1:1) with mucoadhesive polymers (carbopol 934 P and chitosan). The formulations were evaluated for sol-gel transition temperature, in-vitro drug release and in-vivo mucociliary transit time. Further, optimal intranasal gel formulations were tested for in-vivo pharmacokinetic behavior, nasal toxicity studies and brain uptake studies. It was found that optimal formulations had acceptable gelation temperature (28-33 °C) and adequate in-vitro drug release profile. Pharmacokinetic study in rabbits showed significant (p < 0.05) improvement in bioavailability (four- to six-folds) of the drug from intranasal gels than oral solution. Chronic exposure studies in Wistar rats showed that these intranasal gels were non-irritant and non-toxic to rat nasal mucosa. Estimation of RM in rat brain tissue showed significant (p < 0.01) improvement in uptake of RM form intranasal gel formulations than nasal solution.