Ocular and cardiac beta-antagonism by timolol prodrugs, timolol and levobunolol.

Abstract

Topically applied O-butyryl timolol, O-pivaloyl timolol and levobunolol (0.25 micrograms) antagonized isoproterenol-induced ocular hypotension for 8 hrs whereas timolol (0.25 micrograms) was shorter acting (4 hrs). Timolol (25 micrograms) produced greater antagonism of isoproterenol-induced tachycardia than did O-butyryl and O-pivaloyl timolol (25 micrograms). These results suggest that, at similar doses, O-butyryl and O-pivaloyl timolol produce high concentrations of timolol in ocular tissues and undergo redistribution more slowly into the systemic circulation than does topical timolol. Under certain circumstances, prodrugs may provide a mechanism for increasing selectivity and extending the duration of action in the target organ as well as decreasing systemic effects.

• Authors: D E Potter, D J Shumate, H Bundgaard, V H Lee
• Journal: Current eye research (Curr Eye Res) Vol. 7 Issue 8 Pg. 755-9 (Aug 1988) ISSN: 0271-3683 [Print] England
• PMID: 2903009 (Publication Type: Journal Article)

Chemical References

• Adrenergic beta-Antagonists
• Prodrugs
• Timolol
• Levobunolol
• Isoproterenol

Topics

• Adrenergic beta-Antagonists (pharmacology)
• Animals
• Eye (drug effects)
• Heart (drug effects)
• Heart Rate (drug effects)
• Intraocular Pressure (drug effects)
• Isoproterenol (antagonists & inhibitors, pharmacology)
• Levobunolol (pharmacology)
• Male
• Prodrugs (pharmacology)
• Rabbits
• Timolol (pharmacology)