M. Zignani et al., SUBCONJUNCTIVAL BIOCOMPATIBILITY OF A VISCOUS BIOERODABLE POLY(ORTHO ESTER), Journal of biomedical materials research, 39(2), 1998, pp. 277-285
The biocompatibility of a viscous poly(ortho ester) (POE) intended for
prolonged intraocular drug delivery was studied. This hydrophobic and
bioerodable carrier was subconjunctivally injected in rabbits and eva
luated both clinically and histologically. To assess the cause of the
triggered transient acute inflammatory reaction, the two monomers, the
intermediate and final degradation products, and the local toxicity o
f different solvents used during the polymer preparation were tested.
Since the two initial monomers and the intermediate degradation produc
ts induced only moderate inflammation, the main acute inflammatory rea
ction is attributed to the formation of an acidic by-product, which ha
s been monitored in vitro by measuring the progressive decrease of the
environmental pH. The influence of the sterilization procedure on tis
sue biocompatibility was established by comparing two polymers of simi
lar molecular weight: one after gamma-sterilization, and an asepticall
y synthesized one. The biocompatibility was significantly improved by
avoiding irradiation of the polymer. (C) 1998 John Wiley & Sons, Inc.