Abstract
Introduction::
Vinblastine and doxorubicin are chemotherapy drugs used to treat cancers, including breast and lung cancer. The mechanism of action for vinblastine involves capping microtubule ends, thus inhibiting microtubule assembly. Doxorubicin binds to DNA, inhibiting topoisomerase II to prevent replication.
Purpose::
To determine the in vitro transscleral permeability of the anti-cancer drugs, vinblastine and doxorubicin, as possible treatment for intraocular tumors.
Methods::
Human scleral tissue was mounted in a Lucite block perfusion chamber. The episclera was exposed to 200 µL of fluorescently labeled vinblastine (MW 1043.02; 0.1 mg/mL) and doxorubicin (MW 579.98; 0.33 mg/mL). The inner surface of the sclera, lamina fusca, was perfused with BSS at 15 mmHg. Perfusate fractions were collected every hour over 24 hrs, and fluorescence was measured with a fluorometer. After 24 hrs, cryosections of the sclera were obtained to visually identify the fluorescently labeled drug in the sclera using an epifluorescent microscope.
Results::
The scleral Ktrans of vinblastine and doxorubicin were 4.05 X 10-6 cm/sec and 5.64 X 10-7 cm/sec respectively. A fluorescent gradient was visible in the sclera after each 24 hr experiment was completed.
Conclusions::
Vinblastine and doxorubicin were able to diffuse across the human sclera and could be coupled with a slow-release vehicle to treat intraocular tumors.
Keywords: sclera • tumors