Formulation and Characterization of Metformin Loaded Solid Lipid Nanoparticles for Management of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) affects approximately 90% of diabetic patients globally, requiring effective pharmacological interventions for optimal glycemic control. Metformin hydrochloride, a first-line antidiabetic agent, belongs to Biopharmaceutics Classification System (BCS) Class III with high solubility but poor membrane permeability, resulting in limited oral bioavailability of 50-60%. Solid lipid nanoparticles (SLNs) offer a promising strategy to overcome these biopharmaceutical limitations.

This study aimed to formulate and characterize metformin-loaded solid lipid nanoparticles (MTF-SLNs) using hot melt homogenization-ultrasonication technique to enhance drug permeability, bioavailability, and therapeutic efficacy in T2DM management.

MTF-SLNs were prepared using hot homogenization followed by ultrasonication method employing stearic acid as the solid lipid, polysorbate 80 as surfactant, and sorbitol as cryoprotectant. The formulations were systematically optimized and characterized for particle size, polydispersity index (PDI), zeta potential, entrapment efficiency, surface morphology, drug-excipient compatibility, crystallinity, and in vitro drug release profile. Stability studies and comparative dissolution studies were performed to assess formulation performance.

The optimized MTF-SLN formulation exhibited excellent physicochemical characteristics with mean particle size of 262.1 nm, PDI of 0.352, zeta potential of - 42.5 mV, and high entrapment efficiency of 95.8%. Transmission electron microscopy confirmed spherical morphology with smooth surface. Differential scanning calorimetry revealed amorphous state of metformin within the lipid matrix. The formulation demonstrated sustained drug release pattern with 78.3% release over 12 hours following Higuchi kinetics. Permeability studies showed 5-fold enhancement compared to pure metformin.

Metformin-loaded solid lipid nanoparticles represent a viable and effective nanocarrier system for enhanced oral delivery of metformin in T2DM management. The formulation demonstrated improved permeability, sustained release characteristics, and enhanced stability, offering potential for reduced dosing frequency and improved patient compliance.