PLGA Microparticles Entrapping Chitosan-Based Nanoparticles for the Ocular Delivery of Ranibizumab

Abstract

Age-related macular degeneration (AMD) is the leading cause of certified vision loss worldwide. The standard treatment for neovascular AMD involves repeated intravitreal injections of therapeutic proteins directed against vascular endothelial growth factor, such as ranibizumab. Biodegradable polymers, such as poly(lactic-co-glycolic acid) (PLGA), form delivery vehicles which can be used to treat posterior segment eye diseases, but suffer from poor protein loading and release. This work describes a 'system-within-system', PLGA microparticles incorporating chitosan-based nanoparticles, for improved loading and sustained intravitreal delivery of ranibizumab. Chitosan-N-acetyl-L-cysteine (CNAC) was synthesized and its synthesis confirmed using FT-IR and 1 H NMR. Chitosan-based nanoparticles comprised of CNAC, CNAC/tripolyphosphate (CNAC/TPP), chitosan, chitosan/TPP (chit/TPP) or chit/TPP-hyaluronic acid (chit/TPP-HA) were incorporated in PLGA microparticles using a modified w/o/w double emulsion method. Nanoparticles and final nanoparticles-within-microparticles were characterized for their protein-nanoparticle interaction, size, zeta potential, morphology, protein loading, stability, in vitro release, in vivo anti-angiogenic activity and effects on cell viability. The prepared nanoparticles were 17 -350 nm in size and had zeta potentials of -1.4 to +12 mV. Microscopic imaging revealed spherical nanoparticles on the surface of PLGA microparticles for preparations containing chit/TPP, CNAC and CNAC/TPP. Ranibizumab entrapment efficiency in the preparations varied between 13 -69% and was highest for the PLGA microparticles containing CNAC nanoparticles. This preparation also showed the slowest release with no initial burst release compared to all other preparations. Incorporation of TPP to this formulation increased the rate of protein release and reduced entrapment efficiency. PLGA microparticles containing chit/TPP-HA showed the fastest and near-complete release of ranibizumab. All of the prepared empty particles showed no effect on cell viability up to a concentration of 12.5 mg/mL. Ranibizumab released from all preparations maintained its structural integrity and in vitro activity. The chit/TPP-HA preparation enhanced anti-angiogenic activity and may provide a potential biocompatible platform for enhanced anti-angiogenic activity in combination with ranibizumab. In conclusion, the PLGA microparticles containing CNAC nanoparticles, showed significantly improved ranibizumab loading and release profile. This novel drug delivery system may have potential for improved intravitreal delivery of therapeutic proteins, thereby reducing the frequency, risk and cost of burdensome intravitreal injections.

Polysaccharides in Ocular Drug Delivery

“…Elsaid et al [162] studied ranibizumab delivery using a "system-within-system" of PLGA-microspheres that contained nanoparticles. The polysaccharide nanoparticles were based on HA (MW 1500 kDa), chitosan (MW ≤ 400 kDa, degree of deacetylation 80-95%), and chitosan-N-acetyl-l-cysteine (CNAC).…”

A Targeted Nanoprobe Based on Carbon Nanotubes-Natural Biopolymer Chitosan Composites

“…The same procedure has been followed for the preparation of the control probe, FITC-SWCNT-FA, and PPa-SWCNT-FA. Here, chitosan was chosen as it is a natural biocompatible biopolymer with favorable physicochemical properties and can potentially enhance the therapeutic effect [26,27]. Chitosan not only provides an appropriate biological interface to bind FA, PPa and FITC, but also provides a means to effectively disperse the as-prepared PPa/FITC-SWCNT-FA in aqueous solution.…”

Targeted Intraceptor Nanoparticle for Neovascular Macular Degeneration: Preclinical Dose Optimization and Toxicology Assessment

“…31 Although the current study clearly demonstrates that intravenous delivery of PLGA-based RGD.Flt23k.NPs can effectively reduce CNV lesions, this nanoparticle delivery system can be further improved. Elsaid et al 32 developed PLGA-based nanoparticles with chitosan, improving the delivery of intravitreal ranibizumab (Lucentis) to CNV lesions so that it was 50% better than PLGA-based nanoparticles alone. In addition, we found that RGD.Flt23k.NP efficacy plateaus at a 30 mg dose, with a maximal reduction in CNV lesion size of 30%.…”