Abstract
Purpose :
The purpose of this study was to investigate the use of poly (lactic-co-glycolic acid) (PLGA) based nanoparticles to deliver prophylactic vancomycin (VAN) for two weeks following ocular surgery.
Methods :
VAN was encapsulated in hydrolytically degradable acid terminated PLGA based nanoparticles. Nanoparticles were synthesized using a double emulsion processes. Lactide:glycolide (PL:GA) ratios and molecular weight were varied to assess the release characteristics of the nanoparticles. VAN release profiles were conducted at 37°C; at predetermined intervals, samples were analyzed via light spectroscopy using a NanoDrop™ 2000/2000C (280nm, E1% 40) to quantify VAN concentration.
Results :
Nanoparticle encapsulation efficiency was 26 ± 5% for all protocols. PL:GA ratio and molecular weight (MW) did not appear to affect the initial burst of drug (drug release within the first 24 hours) from the nanoparticles (207 ± 3 mg/ml and 204 ± 3 mg/ml for PLGA 75:25; MW 4,000-15,000 and PLGA 50:50; MW 7,000-17,000, respectively). Nanoparticles synthesized from a combination of two different PL:GA ratios (equal parts 75:25 and 50:50) demonstrated a higher initial burst of drug (605 ± 1 mg/ml). Following the initial burst, nanoparticles released a steady level of 8 ± 5 mg/ml, 11 ± 5 mg/ml, and 3 ± 3 mg/ml for PLGA 75:25, PLGA 50:50, and 50% combined nanoparticles, respectively. PL:GA ratio and molecular weight did not demonstrate a strong influence on early release characteristics. The combined polymer system released the smallest amount following a large initial burst.
Conclusions :
This study demonstrated that while a combined polymer system does not improve release characteristics, nanoparticles fabricated from PLGA 75:25 or PLGA 50:50 may have promise for application as a vehicle for short term, prophylactic antibiotic ocular drug delivery.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.