Ultrasound combined blood-brain barrier targeting brain delivery of four-in-one molecular aggregates for the enhancement of anesthetic efficacy and toxicity reduction via propofol-etomidate synergistically inhibition GABA receptor

To enhance the anesthetic efficacy and reduce toxic side effects, a strategy is proposed involving the utilization of general anesthetics of Propofol (Pro) and Etomidate (Eto) to synergistic inhibition GABA receptors simultaneously. Four-in-one molecular aggregates were prepared to implement this strategy, which comprised of Pro and Eto with the bridging molecule monoglyceride monooleate (GMO) and surfactant F127 through intermolecular forces. The blood-brain barrier (BBB) targeted lactoferrin (LF) is affixed to their surface, obtaining the final molecular aggregates. By employing lactoferrin enrich aggregates to the BBB, followed by ultrasound combine microbubbles to open the BBB, a remarkable 4.5-fold enhancement in brain drug delivery was achieved. The molecular aggregates group maintained stable parameters of heart rate, diastolic blood pressure, and systolic blood pressure. A notable increase of more than twice therapeutic index (TI) value was observed, implying their higher anesthesia efficiency and reduced toxicity. Electroencephalogram (EEG) experiments demonstrate a significant elevation in the proportion of δ waves from 28% to 80% for aggregates, accompanied by a nearly fivefold reduction in the proportion of θ waves, meaning a significant improvement in synergistic anesthesia effectiveness (interaction index 0.289) with lower drug dosage. Furthermore, mouse immunofluorescence brain slice experiments suggest Pro and Eto enter the GABA receptor simultaneously, resulting in synergistic inhibition of GABA receptors.