Purpose: The aim of this study was to investigate the extent if recombinant human
hyaluronidase (rhuPH20) can enhance trans-scleral penetration of sub-Tenon's dexamethasone
(DM) into the posterior segment of the eye.
Methods: rhuPH20 was purified from conditioned media through a series of ion exchange,
hydrophobic interaction, aminophenylboronate, and hydroxyapatite chromatography to
greater than 90% purity based upon specific activity. Only the right eye of each rabbit was
injected. The first group (n = 16) received an injection of DM and rhuPH20, whereas the second
group (n = 16) received DM only. The eyes were enucleated 1, 2, 3, and 6 h after the injection,
and the choroid, retina, vitreous, aqueous, and serum were harvested. DM concentration
was assessed by mass spectrometry. Histology (n = 2) and immunohistochemistry (n =
2) was performed to detect toxicity and the presence of the rHuPH20, respectively.
Results: We observed no histopathologic damage to ocular tissues after sub-Tenon's injection.
This enzyme significantly increased DM level in the choroid and the retina 3 h after administration.
The rise in levels was transient returning to normal levels by 6 h.
Conclusions: Sub-Tenon's coinjection of rHuPH20 with DM resulted in a general increase
in DM levels in ocular tissues and the serum, with significant increase in the choroid and the
retina, 3 h after administration.
