Preparation and In Vitro/Ex Vivo Evaluation of Buccoadhesive Discs of an Anti-Parkinson Drug: Relationship between Mucoadhesivity, Drug Release and Permeability

Background: Selegiline hydrochloride (Sel) is a drug applied for the therapy of early‐step Parkinson's disease. In usual clinical doses, it is an elective irreversible MAO-B inhibitor. This study intended to formulate mucoadhesive microspheres of selegiline with the objective of improving the therapeutic efficacy, patient compliance and bioavailability. Methods: The microspheres were prepared by emulsion solvent evaporation method (O1/ O2) using hydroxypropyl methylcellulose (HPMC). In the current study, bucco‐adhesive microspheres were prepared with different drug to polymer ratios and characterized by encapsulation efficiency, particle size, Differential Scanning Calorimetry (DSC), FTIR Fourier Transform Infrared Spectroscopy (FTIR), flowability, the degree of swelling and surface pH, mucoadhesive character, retentive time, and drug release studies. Results: The best drug to polymer ratio in microspheres was 1:2 (as F1). The production yield microspheres F1 showed production yield of 84.79%, mean particle size of 744.73 μm and loading efficiency of 53.33%. The DSC exhibited the property of selegiline loaded microspheres changed to amorphous form. The FTIR spectrum proposed that the drug kept its chemical stability during the emulsification process. The results showed that the microspheres of F1 had faster release than the microspheres of F2 (1:4), F3 (1:6), and commercial tablet (p<0.05). The microspheres did not exhibit good retention time properties (276.66‐329.66 min). The results of mucoadhesion strength (8.3‐18.3 g/cm2) and surface pH of discs (6.44‐6.97) showed the better characterization of microspheres in buccal. Conclusion: The formulations were found to be appropriate candidates for the improvement of microspheres for the remedial objects.