Development of chitosan/sodium carboxymethyl cellulose-based polyelectrolyte complex of dexamethasone for treatment of anterior uveitis

Abstract

Anterior uveitis is one of the most prevalent forms of ocular inflammation caused by infections, trauma, and other idiopathic conditions if not treated properly, it can cause complete blindness. 
Therefore, this study aimed to formulate and evaluate dexamethasone sodium phosphate (DSP) loaded polyelectrolyte complex (PEC) nanoparticles (NPs) for the treatment of anterior uveitis. DSP-loaded PEC-NPs were formed through complex coacervation by mixing low molecular weight chitosan and the anionic polymer carboxy methyl cellulose. The formulations were optimized using Box-Behnken design and evaluated the effect of independent variables: Chitosan concentration, CMC concentration, and pH of chitosan solution on the dependent variables: particle (PS), Polydispersity Index (PDI), pH of the formulation, and % entrapment efficacy (%EE). The PS, PDI, ZP, and pH of the optimized formulation were found 451±82.0995nm, 0.3807±0.1862, +20.33±1.04mV and 6.8367±0.0737 respectively. The %EE and drug loading of formulation were 61.66±4.2914% and 21.442±1.814% respectively. In vitro drug release studies of optimized formulation showed the prolonged release up to 12 hours whereas, the marketed formulation showed the burst release 85.625 ± 4.3062% in 1 hour and 98.1462± 3.0921% at 6 h, respectively. FTIR studies suggested the effective incorporation of the drug into the PEC-NPs formulation whereas DSC and XRD studies showed the amorphized nature of the drug in the formulation. TEM study showed self-assembled, nearly spherical, core-shell nanostructures. The corneal permeation study showed higher permeation of the drug from PEC-NPs compared to the marketed formulation. HET-CAM test of the optimized formulation revealed non-irritant and safe for ocular administration. Therefore, DSP-loaded PEC-NPs are an effective substitute for conventional eye drops due to their ability to increase bioavailability through longer precorneal retention duration and sustained drug release.