Ethyl lactate-ethanol-water cosolvent for intravenous theophylline

Theophylline was dissolved in an ethyl lactate-ethanol-water cosolvent system and administered intravenously to rabbits. There were no observed differences in theophylline pharmacokinetics in rabbits administered in the cosolvent system when compared to theophylline administered as Aminophylline Injection USP, with the half-life being 4.5 hours and 4.3 hours respectively. Theophylline dissolved in the cosolvent system caused less erythrocyte hemolysis when exposed to blood in vitro than Aminophylline Injection USP. There were no observed toxicities in any rabbits during intravenous administration of theophylline dissolved in the cosolvent system or for Aminophylline Injection USP.