Comparative evaluation of propofol in nanoemulsion with solutol and soy lecithin for general anesthesia

Identification of Brain Regions Activated by Sevoflurane and Propofol and Regional Changes in Gene Expression

General anesthetics have different efficacies and side effect incidences based on their mechanism of action. However, detailed comparative studies of anesthetics are incomplete. In this study, target brain regions and gene expression changes in these brain regions were determined for sevoflurane and propofol to understand the mechanisms that cause differences among anesthetics. Rats were anesthetized with sevoflurane or propofol for 1 hr, and brain regions with anesthesia-induced changes in neuronal activity were examined by immunohistochemistry and in situ hybridization for c-Fos. Among the identified target brain regions, gene expression analysis was performed in the habenula, the solitary nucleus and the medial vestibular nucleus from laser microdissected samples. Genes altered by sevoflurane and propofol were different and included genes involved in the incidence of postoperative nausea and vomiting and emergence agitation, such as Egr1 and Gad2. GO enrichment analysis showed that the altered genes tended to be evenly distributed in all functional category. The detailed profiles of target brain regions and induced gene expression changes of sevoflurane and propofol in this study will provide a basis for analyzing the effects of each anesthetic agent and the risk of adverse events.

Physical and Chemical Compatibility of Etomidate and Propofol Injectable Emulsions

INTRODUCTION

The mixture of etomidate and propofol is widely used in clinical practice to improve efficacy of general anesthesia and to minimize side effects. As a thermodynamically unstable system, emulsion is prone to destabilization through mechanisms including coalescence, flocculation, and creaming. Such unwanted phenomenon can induce fat embolism after intravenous administration. This study was aimed to investigate the physical and chemical stability of the mixture of etomidate and propofol in the dosage form of emulsion.

METHODS

This compatibility study focused on the critical quality attributes (CQAs) of drug-containing emulsions, such as appearance, pH, particle size and distribution, zeta potential, the observation under centrifugation, and drug content and impurity.

RESULTS

As the results, there were no significant changes in the CQAs of the mixed emulsions up to 24 h after mixing at refrigeration temperature (4°C), room temperature (25°C), and body temperature (37°C).

CONCLUSIONS

These results demonstrate that etomidate emulsion is physically and chemically compatible with propofol emulsions up to 24 h at 4°C, 25°C, and 37°C, suggesting that etomidate and propofol can be administrated in mixture without adversely affecting product characteristics, at least in vitro.

Water in the human body: An anesthesiologist's perspective on the connection between physicochemical properties of water and physiologic relevance

The unique structure and multifaceted physicochemical properties of the water molecule, in addition to its universal presence in body compartments, make water a key player in multiple biological processes in human physiology. Since anesthesiologists deal with physiologic processes where water molecules are critical at different levels, and administer medications whose pharmacokinetics and pharmacodynamics depend on interaction with water molecules, we consider that exploration of basic science aspects related to water and its role in physiology and pharmacology is relevant to the practice of anesthesiology. The purpose of this paper is to delineate the physicochemical basis of water that are critical in enabling it to support various homeostatic processes. The role of water in the formation of solutions, modulation of surface tension and in homeostasis of body temperature, acid-base status and osmolarity, is analyzed. Relevance of molecular water interactions to the anesthesiologist is not limited to the realm of physiology and pathophysiology. Deep knowledge of the importance of water in volatile anesthetic effects on neurons opens a window to a new comprehensive understanding of complex cellular mechanisms underlying the practice of anesthesiology.