SYNTHESIS AND OPTIMIZATION OF SOLANUM TORVUM EXTRACT-LOADED MESOPOROUS SILICA NANOPARTICLES

Objective: To develop and optimize Solanum torvum extract-loaded mesoporous silica nanoparticles (MSNs) targeting methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Escherichia coli with enhanced physicochemical properties and stability for antimicrobial resistance (AMR) applications. Methods: Mesoporous silica nanoparticles were synthesized using a modified Stöber method. The formulation was optimized using Box-Behnken design with three critical factors: CTAB amount (0.25-1.00 g), TEOS volume (5.00-10.00 ml), and stirring speed (400-600 rpm), targeting minimal particle size and most negative zeta potential. The optimized formulation was characterized for particle size, zeta potential, loading efficiency, morphology (SEM), drug-excipient compatibility (FTIR, DSC), in vitro release profile, and accelerated stability. Results: The 2FI model demonstrated excellent predictive capability for both responses (adjusted R²=0.8640 and 0.9508 for particle size and zeta potential, respectively). Formulation SF6 (CTAB: 1g, TEOS: 7.5 ml, stirring speed: 400rpm) was identified as optimum, exhibiting spherical morphology with particle size of 110.8±2.5 nm, PDI of 0.182±0.011, zeta potential of-32.3±0.7 mV, and loading efficiency of 89.1±0.45%. The formulation showed biphasic sustained release (92.1% over 12 h) and demonstrated moderate stability under accelerated conditions with gradual parameter changes (40 °C/75%RH) for 6 mo with minimal changes in critical parameters (5% increase in particle size, 4.2% decrease in drug content) and exhibited potent antimicrobial activity with MIC values of 8 μg/ml (MRSA) and 16 μg/ml (MDR E. coli). Conclusion: The optimized Solanum torvum extract-loaded MSNs offer a promising nanodelivery system with enhanced stability and sustained release characteristics that could potentially improve bioavailability, reduce dosing frequency, and enhance patient compliance in clinical settings. The formulation's moderate stability profile, while improved compared to free extract, requires further optimization to address storage-related degradation in phytopharmaceutical development, positioning it for future translational studies toward clinical applications.