Abstract
Purpose: :
The anti-vascular endothelial growth factor (VEGF) agents ranibizumab and bevacizumab are used to treat ocular neovascular diseases. There have been recent reports of sustained elevation of intraocular pressure (IOP) after use of either agent which we hypothesize could be due to high molecular weight aggregates.
Methods: :
Enzyme-linked immunosorbent assay (ELISA), size-exclusion chromatography, and polyacrylamide gel electrophoresis (PAGE), were used to analyze repackaged bevacizumab syringes obtained from four outside compounding pharmacies (CP) as well as samples obtained directly from the original glass vial. Microflow imaging (MFI) was used to examine micro-sized particulate material within samples.
Results: :
All syringes contained statistically similar amounts of protein, consisting of immunoglobulin (IgG) heavy and light chains (PAGE). However, two of the three CP batches had significantly less functional IgG in solution (ELISA). Additionally, two different CP’s contained ten-fold the number of micron-sized particulate matter as compared to vehicle controls, including one with the lowest IgG content (~50%) determined by ELISA.
Conclusions: :
There are significant differences in IgG concentration measured from repackaged bevacizumab syringes. A trend exists for an increase in micron-sized protein aggregates with the decrease in IgG concentration. Large particulate matter within some samples may lead to obstruction of aqueous outflow and subsequent elevation in IOP. Further studies are warranted to explore these findings.
Keywords: intraocular pressure • vascular endothelial growth factor • protein structure/function