Design of Experiments (Doe) for the Development and Evaluation of Empagliflozin-Loaded Microspheres

The present study aimed to formulate and evaluate Empagliflozin microspheres using the solvent evaporation technique to develop a sustained-release oral drug delivery system for improved therapeutic efficacy and patient compliance in the management of Type 2 Diabetes Mellitus. Eight formulations (F1–F8) were prepared using varying concentrations of sodium alginate and ethyl cellulose as release-retarding polymers. Prior to formulation, preformulation studies including organoleptic evaluation, solubility, melting point determination, UV spectrophotometric analysis, and FTIR compatibility studies were carried out. Empagliflozin exhibited a λmax at 225 nm, and FTIR studies confirmed the absence of significant drug–excipient interactions, indicating good compatibility. The prepared microspheres were evaluated for particle size, zeta potential, percentage yield, surface morphology, drug entrapment efficiency, in-vitro drug release, release kinetics, and stability. The particle size ranged from 746 to 869 µm, while zeta potential values ranged from −20 to −36 mV, indicating acceptable physical stability. Percentage yield varied between 72.59% and 85.59%, and drug entrapment efficiency ranged from 76.39% to 92.53%. Scanning electron microscopy revealed spherical, discrete microspheres with smooth surfaces. Among all formulations, F8 exhibited the best performance with a particle size of 746 µm, zeta potential of −24 mV, percentage yield of 85.59%, and drug entrapment efficiency of 92.53%. In-vitro dissolution studies demonstrated sustained drug release over 8 hours, with formulation F8 achieving the highest cumulative drug release of 98.22%. Drug release kinetic analysis showed that the optimized formulation followed Zero-order kinetics (R² = 0.984), indicating nearly constant drug release with diffusion contributing to the release mechanism. Stability studies performed for 90 days under ICH-recommended conditions revealed no significant physical changes and only a slight reduction in drug release, confirming the stability of the optimized formulation. The study concludes that the solvent evaporation technique is an effective approach for preparing Empagliflozin microspheres with excellent encapsulation efficiency, sustained drug release, and satisfactory stability. The optimized formulation (F8) demonstrated promising characteristics as a sustained-release oral delivery system that may improve bioavailability, reduce dosing frequency, and enhance patient compliance. Further in-vivo pharmacokinetic and pharmacodynamic studies are recommended to establish its clinical applicability.