Design Formulation and in vitro Evaluation of Gastroretentive Microspheres of Selegiline Hydrochloride for Parkinson’s Disease by Design Expert

Introduction: Selegiline hydrochloride is primarily used to treat Parkinson’s disease. Selegiline hydrochloride mucoadhesive microspheres were prepared to improve the bioavailability of the drug and its appropriate therapeutic performance. Materials and Methods: The ionic gelation process was used to formulate the gastroretentive mucoadhesive microspheres using different polymers such as gum kondagogu (150 to 450 mg), karaya gum (10 to 70 mg), and carbopol 940P (150 to 450 mg) of different concentrations in preliminary trial formulations (SM1-SM14) after performing preformulation studies. Optimisation of selegiline hydrochloride mucoadhesive microspheres (SHM1 to SHM11) was done by optimizing. The study employed independent variables-Karaya gum concentration (10, 40, and 70 mg) and stirring speed (500, 1000, and 1500 rpm)-alongside dependent variables: percentage entrapment efficiency, particle size, and cumulative drug release. Design Expert 13 software employing Central Composite Design facilitated optimization. ANOVA elucidated the influence of these variables on the dependent ones, providing insights into the interplay between polymer concentration, stirring speed, and the measured outcomes. For optimised formulation, SEM was done to determine structural features. Results: Initial investigations revealed that, aside from gum kondagugu, formulations containing carbopol 934P demonstrated superior mucoadhesion and drug release characteristics. The optimised formulation SHM12 (given by Design Expert 13 software in Overlay Plot) having 64.31 mg of Karaya Gum at stirring speed 1500 rpm showed 84.84% entrapment efficiency, 450 μm particle size, and 96.53 cumulative percent drug release. Results were confirmed experimentally. Conclusion: The study concluded that the developed mucoadhesive microspheres for selegiline hydrochloride exhibited enhanced cumulative drug release, ultimately enhancing bioavailability.