Formulation and Evaluation of Multiparticulate Pellet Systems for Antidiabetic and Antihypertensive Drugs: Application of Extrusion– Spheronization and Solution Layering Techniques

The present study focuses on the development and comprehensive evaluation of sustained and controlled release multiparticulate pellet formulations for three therapeutic agents: Tolbutamide, Saxagliptin, and Verapamil. The primary objective was to enhance drug release profiles and patient compliance using extrusion–spheronization and solution layering techniques. Tolbutamide and Verapamil were formulated into matrix-based sustained release pellets using hydrophilic polymers (HPMC) and plasticizers (MCC), while Saxagliptin pellets were prepared via solution layering on nonpareil seeds with optional Eudragit RS 100 coating for controlled release. Optimization of formulation parameters was performed using factorial design.All formulations exhibited excellent flow properties, narrow particle size distribution (500–850 µm), and satisfactory morphology with minimal friability (<1%). Drug content uniformity across all batches remained within pharmacopeial limits (RSD < 2%). In vitro drug release studies showed that Tolbutamide was released steadily (98.7% in 5 hours), Saxagliptin was released in a zero-order controlled way (98.1% in 5 hours), and Verapamil was released in a pHsensitive way (92.5% in 6 hours). These results fit Higuchi, zero-order, and first-order kinetic models, respectively. These results show that pelletization methods can be used to customize the release kinetics of drugs with different physical and chemical properties and therapeutic goals. This shows that they are good for making strong oral controlled release dosage forms.