Formulation and Evaluation of a Novel Ocular Drug Delivery System for the Treatment of Glaucoma with Simbrinza

Abstract

Glaucoma is a chronic ocular disease requiring sustained drug delivery for effective treatment. This study presents the formulation and evaluation of a novel ocular drug delivery system using Poly(lactic-co-glycolic acid) (PLGA) nanoparticles for the combined glaucoma treatment with brinzolamide and brimonidine tartrate, as found in the drug Simbrinza. The PLGA nanoparticles exhibited an average hydrodynamic diameter of 178 ± 5 nm and a low Polydispersity Index (PDI) of 0.15 ± 0.03, ensuring uniform size distribution and efficient drug penetration. Zeta potential measurements revealed a stable surface charge of -27 ± 2 mV, enhancing colloidal stability. High drug loading efficiencies of 20% w/w for brinzolamide and 15% w/w for brimonidine tartrate were achieved, indicating effective drug encapsulation. Scanning and transmission electron microscopy confirmed uniform spherical morphology and a core-shell structure, ensuring structural integrity. In vitro drug release studies demonstrated sustained release profiles over 72 hours, following a diffusion-controlled mechanism with high correlation coefficients (R²) of 0.98 for brinzolamide and 0.97 for brimonidine tartrate. These findings suggest the potential of this PLGA nanoparticle-based delivery system for efficient and prolonged glaucoma therapy, promising improved patient compliance and therapeutic efficacy.