Design and Optimization of Ethyl Cellulose-Based Polymeric Nanoconjugates for Delivery of Quetiapine Fumarate

Objective: To develop and optimize ethyl cellulose-based polymeric nanoconjugates for sustained delivery of quetiapine fumarate in order to improve its physicochemical characteristics, encapsulation efficiency, and controlled-release behavior. Methods: Ethyl cellulose-based polymeric nanoconjugates were prepared using a solvent evaporation technique. A Plackett-Burman design was employed to screen critical formulation variables, followed by Box-Behnken design for optimization. The optimized formulation was characterized for particle size, polydispersity index, zeta potential, encapsulation efficiency, morphology, and physicochemical compatibility using SEM, FTIR, and DSC. In vitro drug release and stability studies were also conducted. Results: The optimized nanoconjugates exhibited a particle size of approximately 321 nm with a low polydispersity index, indicating uniform distribution. High entrapment efficiency (~69%) was achieved. Morphological examination showed the presence of smooth-surface and spherical particles, whereas FTIR and DSC demonstrated compatibility of drugs and polymers and successful encapsulation. The formulation exhibited a biphasic pattern of drug release which is sustained up to 24 h, after initial first-order and diffusion-controlled kinetics. Stability experiments established that there was little change when standard storage conditions were used. Conclusion: The developed ethyl cellulose nanoconjugates provide an effective strategy for sustained delivery of quetiapine fumarate, improving its physicochemical and release characteristics. This system has a great potential toward increasing the therapeutic efficacy and patient compliance, which requires further in vivo and clinical research.