Abstract
Purpose: :
To develop Avastin nanoparticles maintaining the biological activity of Avastin for the treatment of Age Related Macular Degeneration, and to establish an effective direct ELISA for Avastin testing in nanoparticles.
Methods: :
Double emulsion method was employed to encapsulate Avastin into Poly (lactide-co-glycolide) (PLGA) nanoparticles. To maintain the biological potency of Avastin during nanoparticle preparation, different strategies were developed to stabilize the encapsulated Avastin, including the selections of suitable organic solvents, aqueous phases, stabilizers, and effective preparation protocols. Direct ELISA was afterward applied to test entrapment efficiency and drug loading in nanoparticles and to examine whether the encapsulated Avastin still maintains biological activity. A mixture of dimethyl sulphoxide (DMSO) and water (4:1) was used as solvent for the ELISA instead of aqueous buffer.
Results: :
Based on formula optimization, ethyl acetate and phosphate buffer with pH 6.2 were selected as oil phase and aqueous phase solvent respectively to prepare nanoparticles, and 6% of trehalose is applied as stabilizer. Entrapment efficiency was significantly enhanced from less than 2% to 50%. A mixture of DMSO and water (4:1) was shown to be suitable for extracting Avastin from nanoparticles and also as an ELISA solvent. The detection range of the direct ELISA is from 0.5 ug/ml to 12 ug/ml, and the r2 value reaches 0.9995. Results from ELISA showed that the encapsulated Avastin was biologically active.
Conclusions: :
For the first time Avastin nanoparticles with high entrapment efficiency and ability to maintain biological activity were prepared for treating Age Related Macular Degeneration. A novel solvent was successfully employed to perform direct ELISA for testing nanoparticle properties.
Keywords: age-related macular degeneration • vascular endothelial growth factor • choroid: neovascularization