FORMULATION DEVELOPMENT AND CHARACTERIZATION OF ION AND PH DUAL ACTIVATED NASAL IN-SITU GEL CONTAINING LEVODOPA AND CARBIDOPA FOR THE TREATMENT OF PARKINSON’S DISEASE

Levodopa suffers from low oral bioavailability and less than 1% of the drug reaches the brain because of its peripheral degradation. This study aimed to prepare a nasal in-situ gel of levodopa and carbidopa to provide prolonged drug release, improve bioavailability, and increase drug uptake by the brain. Preliminary studies were carried out using different polymers. The concentration of polymer to be employed for the development of the formulations was deduced by carrying out placebo studies (F1-F12). All the batches were assessed for various parameters such as pH, viscosity, gelation time, and mucoadhesive strength. Out of 12 placebos, F11 which is pH and ion dual activated in-situ formulation showed satisfactory results. Therefore, F11 formulation was selected to prepare levodopa and carbidopa nasal in-situ gel. Drug incorporated formulation was found to have a viscosity of 2870.13 cps, assay of 95.7% of levodopa and 100.83% of carbidopa, and gelation time of 35 s, and the in-vitro drug release of levodopa and carbidopa after 8 h is 95.7% and 99.38%, respectively. Ex-vivo drug release is 97.9% and 99.2% within 5 hours for levodopa and carbidopa respectively. The histopathological study revealed that there was no cell necrosis and no loss of the epithelium. These results indicate that the in-situ gel was able to maintain its viscosity over time and was able to release the drug at a prolonged rate. These results suggest that the developed Levodopa and carbidopa nasal in-situ gel may be the promising drug delivery for the treatment of Parkinson’s disease.