In Vitro and In Vivo Evaluation of Lactoferrin-Modified Liposomal Etomidate with Enhanced Brain-Targeting Effect for General Anesthesia

Abstract

Etomidate is a general anesthetic that has shown good hemodynamic stability without significant cardiovascular or respiratory depression. Despite several kinds of dosage forms having been reported for this drug, formulation types are very limited in clinical practice, and brain-targeted formulations for this central nervous system (CNS) drug have been rarely reported. Moreover, studies on the biocompatibility, toxicity, and anesthetic effects of the etomidate preparations in vivo were inadequate. The present study was to develop lactoferrin-modified liposomal etomidate (Eto-lip-LF) for enhanced drug distribution in the brain and improved anesthetic effects. Eto-lip-LF had good stability for storage and hemocompatibility for intravenous injection. Compared with the non-lactoferrin-containing liposomes, the lactoferrin-modified liposomes had notably enhanced brain-targeting ability in vivo, which was probably realized by the binding of transferrin with the transferrin and lactoferrin receptors highly distributed in the brain. Eto-lip-LF had a therapeutic index of about 25.3, higher than that of many other general anesthetics. Moreover, compared with the commercial etomidate emulsion, Eto-lip-LF could better achieve rapid onset of general anesthesia and rapid recovery from anesthesia, probably due to the enhanced drug delivery to the brain. The above results demonstrated the potential of this lactoferrin-modified liposomal etomidate to become an alternative preparation for clinical general anesthesia.