Mitomycin C dissolved in a reversible thermosetting gel: target tissue concentrations in the rabbit eye.

AIMS: To determine whether a new, reversible thermosetting gel enhances mitomycin C transfer to target ocular tissues in the rabbit eye. METHODS: A 0.1 ml solution of mitomycin C containing 0.22 microgram, 2.9 micrograms, or 28 micrograms of the agent dissolved in a reversible thermosetting gel consisting of methylcellulose, citric acid, and polyethylene glycol was injected subconjunctivally in 30 New Zealand albino rabbits. Scleral and conjunctival tissues were excised at 0.5, 1, 2, 4, or 24 hours after the injection and mitomycin C concentrations in these tissues were determined by high performance liquid chromatography. The concentration over time was approximated to a single exponential curve, and initial mitomycin C concentrations, time constants, and half life values were determined. Finally, the areas under the curves (AUCs) between 0.5 and 24 hours were calculated. RESULTS: The mitomycin C concentrations in the target tissues were dose dependent and decreased rapidly over 24 hours. Both the initial mitomycin C concentrations as well as AUCs in these eyes treated with mitomycin C, dissolved in a reversible thermosetting gel, were higher than those in eyes treated similarly in a previous study in which the gel was not used. CONCLUSION: Applied subconjunctivally in the rabbit eye, mitomycin C dissolved in the reversible thermosetting gel enhanced transfer of the agent to the sclera and the conjunctiva.

Effect of mitomycin C dissolved in reversible thermo-setting gel on the outcome of filtering surgery in the rabbit.

PURPOSE: Based on our previous report that showed enhanced transfer of mitomycin C to the sclera and the conjunctiva by dissolving the agent into a reversible thermo-setting gel, we conducted a study to investigate the efficacy of mitomycin C gel in the rabbit. METHODS: We subconjunctivally injected 0.1 mL of the mitomycin C gel solution containing several different amounts of the agent. Trephination was performed in the injected region 24 hours later. Intraocular pressure measurement, photography, and ultrasound biomicroscopic examination of the filtering bleb were conducted 1, 2, and 4 weeks postoperatively. RESULTS: The gel containing 3.0 microg or more mitomycin C significantly enhanced bleb formation and reduction in the intraocular pressure. CONCLUSIONS: The reversible thermo-setting gel seems to help the filtering bleb to survive in the rabbit and deserves further investigation as a new method of mitomycin C application.

[Effect of mitomycin C dissolved in a reversible thermosetting gel on outcome of filtering surgery in the rabbit].

PURPOSE: Based on our previous report that showed enhanced transfer of mitomycin C to the sclera and the conjunctiva by dissolving the antiproliferative in a reversible thermo-setting gel, we conducted a study to investigate the efficacy of the mitomycin C-gel in the rabbit. METHODS: We subconjunctivally injected 0.1 ml of the mitomycin C-gel solution containing several amounts of the drug. Trephination was performed in the injected region 24 hours later. Intraocular pressure measurement, and photography and ultrasound biomicroscopic examination of the filtering bleb were done 1, 2, and 4 weeks postoperatively. RESULTS: The gel containing 3.0 micrograms or more mitomycin C significantly enhanced bleb formation in addition to reducing the intraocular pressure. CONCLUSION: The reversible thermo-setting gel seems to facilitate filtration following glaucoma filtering surgery in the rabbit and deserves further investigation as a new method of mitomycin C application.

Prevention of visual field defect progression with brovincamine in eyes with normal-tension glaucoma.

PURPOSE: A prospective investigation of the effect of brovincamine fumarate, a Ca2+-channel blocker, on visual field changes in normal-tension glaucoma (NTG). METHODS: A total of 28, age- and field-matched, patients with NTG were allocated randomly to either brovincamine fumarate (20 mg 3 times daily) or placebo (3 times daily). The patients were followed at least every 4 months for a minimum of 2.5 years, and visual field examinations were carried out at least every 6 months. The mean follow-up periods (+/-standard deviation) were 39.1 +/- 8.7 months in the brovincamine-treated group and 37.9 +/- 10.1 months in the placebo group. Stepwise discriminant analyses were performed to separate the patients who showed improvement of their visual fields from those who failed to improve in the brovincamine-treated group, and to identify factors that may determine the visual field prognosis of all patients with NTG enrolled in the study. RESULTS: In the brovincamine-treated group, six patients showed visual field improvement, whereas none showed improvement in the placebo group using the Statpac 2 linear regression analysis. Discriminant analyses identified better cold recovery rate and higher initial systolic blood pressure to be significantly contributory to a favorable outcome in the brovincamine-treated group, and the use of brovincamine, better cold recovery rate, and higher initial systolic blood pressure were identified to be significantly contributory to a favorable prognosis in all subjects. CONCLUSION: Brovincamine seems to have a favorable effect on visual field in at least some patients with NTG.