Comment s′assurer de la stabilité d′un glaucome ?

Chitosan-coated PLGA nanoparticles of bevacizumab as novel drug delivery to target retina: optimization, characterization, and in vitro toxicity evaluation

In several ocular diseases, the vascular endothelial growth factor (VEGF) level has been found to be upregulated. Bevacizumab, an anti-VEGF drug, is the most commonly used off level drug for these conditions. Delivery of drug to the posterior site is desired for the effective management of these diseases. The present study was to develop and optimize the chitosan (CS)-coated poly(lactide-co-glycolic acid) (PLGA) nanoparticles (NPs) of bevacizumab for sustained and effective delivery to posterior ocular tissues. NPs were prepared by double emulsion solvent evaporation method and optimized for various variables (i.e., CS concentration, PLGA content, polyvinyl alcohol (PVA) concentration, and sonication time) by employing a 4-factor 3-level Box-Behnken statistical design. NPs were characterized for particle size, polydispersity index (PDI), entrapment efficiency (EE), and in vitro release. Transscleral flux was determined through goat sclera, and ocular tolerance assay was done by Hen's Egg Test chorioallantoic membrane method. The particle size and PDI of the optimized NPs were 222.28 ± 7.45 nm and 0.19 ± 0.08, respectively. The developed NPs showed an EE of 69.26 ± 1.31% with an extended release profile. The flux was significantly higher that is, 0.3204 ± 0.026 μg/cm²/h for the NPs compared to drug solution. Thus, CS-coated PLGA NPs can be potentially useful as ocular drug carriers to target retina.

[Visual field progression after trabeculectomy in primary open-angle glaucoma: preliminary results]

INTRODUCTION

Our purpose was to evaluate the changes in the visual field (VF) after trabeculectomy and to indentify factors influencing variation for a better follow-up of patients with primitive open-angle glaucoma (POAG).

MATERIAL AND METHODS

We conducted a prospective study at the A. Le Dantec Hospital in Dakar, Senegal. Seventeen eyes of POAG patients were studied. The parameters noted for each patient were age, sex, affected eye, pre- and postoperative intra-ocular pressure (IOP), cup disk, sensitivity thresholds on pre- and postoperative perimetry, severity of glaucoma, and medication taken by the patient. Each patient had a frequency doubling technology (FDT) visual field examination before and the after surgery. None of them had an associated pathology that could cause VF troubles. The postoperative visual field was noted. All these parameters were correlated using the chi square test in order to determine factors influencing a threshold variation.

RESULTS

Our patients were new in 70.6% of cases, and the mean age was 45 years. The mean preoperative IOP was 25.7mmHg, 29.4% of the eyes had a cup disk up to 0.7. The VF showed severe glaucoma in 58.8%; 70.6% of eyes had only beta-blocker treatment. Peritomy with limbic hinge was performed in 88.2% of trabeculectomies. No surgical complication was noted. After trabeculectomy, the mean IOP was 14mmHg with a mean decrease of 42.8%. Before surgery, 94.1% of eyes had lower temporal quadrant involvement. For 94.1% of eyes, central vision was preserved. After surgery, progression was better in 18%, stable in 41%, and worse in 41% of cases. Of the factors studied, only age and graded follow-up time from surgery had a statistically significant influence on VF after trabeculectomy.

CONCLUSION

Trabeculectomy was necessary in treatment of POAG, because of poor observance of medical treatment and severity of lesions at the time of diagnosis. The results (59% improvement or stability), in spite of the small sample size, argue in favor of this surgical treatment for some patients with POAG in our country.