Comparison of Topical and Intravenous Administration of WIN 55-212-2 in Normotensive Rabbits

• Published in: Current eye research Vol. 33; no. 10; pp. 857 - 863
• Main Authors: Samudre, Sandeep S., Schneider, Jennifer L., Oltmanns, Matthew H., Hosseini, Alireza, Pratap, Kiran, Loose-Thurman, Patricia, Allen, Robert C., Williams, Patricia B., Lattanzio, Frank A., Sheppard, John D.
• Format: Journal Article
• Language: English
• Published: England Informa UK Ltd 01.01.2008; Taylor & Francis
• Subjects: Administration, Topical; Animals; Benzoxazines - administration & dosage; Benzoxazines - adverse effects; Blood Pressure - drug effects; Cannabinoids - administration & dosage; Cannabinoids - adverse effects; Dose-Response Relationship, Drug; Female; Heart Rate - drug effects; Injections, Intravenous; Intraocular Pressure - drug effects; intravenous; Morpholines - administration & dosage; Morpholines - adverse effects; Naphthalenes - administration & dosage; Naphthalenes - adverse effects; Rabbits; Timolol - administration & dosage; Tocrisolve; Tonometry, Ocular; topical; WIN 55-212-2
• DOI: 10.1080/02713680802419724
• ISSN: 0271-3683

Objective: This study compares the effect of topical versus intravenous (IV) administration of synthetic WIN 55-212-2 (WIN) or timolol on intraocular pressure (IOP). Methods: WIN or timolol were administered either topically or by IV in normotensive New Zealand white rabbits. IOP was measured at baseline and 30, 60, and 120 min after administration (n = 4 per group). Blood pressure (BP) and heart rate (HR) were measured concomitantly with IOP. Results: IV administration of 0.1 mg/kg WIN reduced IOP by 30% after 30 min, which continued to decline for up to 120 min. Timolol injection (25 μ g/kg) also reduced IOP by 25% after 30 min but was not sustained. In comparison, both topical WIN (1.0%) and timolol (0.5%) reduced IOP by 20% from baseline after 30 min. IV injection of either WIN or timolol significantly reduced HR to 155.4 ± 11.4 bpm and 165.9 ± 11.1 bpm, respectively, from a baseline of 256.3 ± 9.9 bpm. Topical administration was well tolerated and did not affect behavior, BP, or HR. Conclusion: Topical administration of either WIN or timolol did not decrease IOP as much as IV administration, but the lack of systemic or local toxicity could make it the safer alternative.