Yamakage Michiaki, Iwasaki Sohshi, Satoh Jun-Ichi, Namiki Akiyoshi
Department of Anesthesiology, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.
Anesth Analg. 2005 Aug;101(2):385-388. doi: 10.1213/01.ANE.0000154191.86608.AC.
Because free propofol is thought to be responsible for pain on injection, we investigated the changes in concentrations of free propofol by modifying two kinds of propofol products in a medium- and long-chain triglyceride (MCT/LCT) emulsion and in an LCT emulsion. The techniques used in this study were 1) mixing 2% lidocaine (10:1), 2) mixing 5% dextrose in acetated Ringer's solution to reduce pH (10:1), and 3) changing the temperature to 4 degrees , 20 degrees , and 36 degrees C. The propofol preparations were dialyzed for 24 h, and the receptor medium was analyzed using high-performance liquid chromatography. The concentration of free propofol in propofol MCT/LCT was significantly smaller by 30% than that in propofol LCT. Neither mixing lidocaine nor cooling reduced the concentrations of free propofol in both products, but the concentrations were reduced by a decrease in pH and by an increase in temperature. Because mixing lidocaine can induce instability in an emulsion of propofol and warming can rapidly induce microbial growth, injection of lidocaine before propofol administration is recommended to reduce the pain on injection. The concentrations of free propofol in propofol MCT/LCT were significantly smaller (by approximately 30%-45%) than those in propofol LCT during any situation in this study.
Neither mixing lidocaine nor cooling reduced the concentrations of free propofol in both products but the concentrations were reduced by a decrease in pH and by an increase in temperature. Propofol medium- and long-chain triglycerides had significantly smaller concentrations by approximately 30%-45% than those in propofol long-chain triglycerides during any situation in this study.
由于游离丙泊酚被认为是注射疼痛的原因，我们通过在中长链甘油三酯（MCT/LCT）乳剂和LCT乳剂中对两种丙泊酚产品进行改性，研究了游离丙泊酚浓度的变化。本研究采用的技术为：1）混合2%利多卡因（10:1）；2）在醋酸林格氏液中混合5%葡萄糖以降低pH值（10:1）；3）将温度分别改变为4℃、20℃和36℃。将丙泊酚制剂透析24小时，并用高效液相色谱法分析受体介质。丙泊酚MCT/LCT中游离丙泊酚的浓度比丙泊酚LCT中的浓度显著低30%。在两种产品中，混合利多卡因和冷却均未降低游离丙泊酚的浓度，但pH值降低和温度升高可降低其浓度。由于混合利多卡因可导致丙泊酚乳剂不稳定，且升温可迅速导致微生物生长，因此建议在给予丙泊酚前注射利多卡因以减轻注射疼痛。在本研究的任何情况下，丙泊酚MCT/LCT中游离丙泊酚的浓度均比丙泊酚LCT中的浓度显著低（约30%-45%）。
在两种产品中，混合利多卡因和冷却均未降低游离丙泊酚的浓度，但pH值降低和温度升高可降低其浓度。在本研究的任何情况下，丙泊酚中长链甘油三酯的浓度比丙泊酚长链甘油三酯的浓度显著低约30%-45%。
