FORMULATION AND IN-VITRO CHARACTERIZATION OF SUMATRIPTAN SUCCINATE -LOADED MUCOADHESIVE MICROSPHERES INCORPORATED IN IN-SITU NASAL GEL

Abstract

Background: Sumatriptan succinate is a selective 5-HT₁ receptor agonist used for the acute treatment of migraine attacks. However, its low oral bioavailability (approximately 15%) due to extensive first-pass metabolism and slow onset of action limits its therapeutic efficacy. Nasal drug delivery offers an alternative route that bypasses hepatic metabolism and provides rapid drug absorption through the rich vascular network of the nasal mucosa. Incorporating mucoadhesive microspheres into an in-situ nasal gel can further enhance drug residence time, control release, and improve patient compliance. Objective: The present study aimed to formulate and evaluate mucoadhesive microspheres of Sumatriptan succinate incorporated into an in-situ nasal gel for sustained release and enhanced nasal bioavailability. Methods: Sumatriptan succinate-loaded mucoadhesive microspheres were prepared using the emulsification cross-linking method with chitosan as the polymer and sodium tripolyphosphate (TPP) as the cross-linking agent. Nine formulations (F1–F9) were developed by varying the polymer-to-drug ratio. The microspheres were evaluated for percentage yield, particle size, drug entrapment efficiency, swelling index, mucoadhesive strength, and invitro drug release. The optimized microspheres were incorporated into a Poloxamer 407-based in-situ nasal gel and evaluated for pH, viscosity, gel strength, and mucoadhesive force. Results: The study revealed that increasing the concentration of chitosan improved yield, drug entrapment efficiency, swelling index, and mucoadhesive strength while reducing drug release rate. The optimized formulation (F9) showed a yield of 77.0 ± 1.8%, entrapment efficiency of 72.3 ± 2.3%, particle size of 35.0 ± 1.9 µm, and sustained drug release (40.8 ± 3.0% at 8 h). The formulated in-situ gel displayed ideal pH (6.2 ± 0.2), viscosity (860 ± 16 cps), and gel strength (43.2 ± 1.5 sec), ensuring compatibility and adequate nasal retention. Conclusion: The developed mucoadhesive microspherebased in-situ nasal gel of Sumatriptan succinate exhibited prolonged drug release, enhanced mucoadhesion, and suitable physicochemical properties for nasal administration. This delivery system could potentially overcome the limitations of conventional oral and parenteral routes, providing rapid onset and sustained therapeutic effect in migraine management.