Sorption of Local Anesthetics by Fat Emulsion with Different Content of Lipid / 医药导报

ABSTRACT

Objective To research sorption of local anesthetic by fat emulsion with different content of lipid in vitro and then to discuss the mechanism of action of fat emulsion for treatment of local anesthetic toxicity. Methods 10%,20%,30% fat emulsion was added to the bupivacaine hydrochloride and ropivacaine hydrochloride.After the mixture was vortexed for 10 mins,it was vibrated in thermostatic water bath at 37 ℃ for 15 h,then centrifugated and got the aqueous phase to HPLC test.The chromatography was carried on a C18column(4.6 mm×250 mm,5 μm ),the mobile phase was composed of acetonitrile-natrium biphosphoricum(2575),the flow rate was 1 mL·min-1,the column temperature was 30 ℃ and the detection wavelength was set at 210 nm. Results Under the condition of this test,the linear ranges and linear equations for bupivacaine hydrochloride and ropivacaine hydrochloride were 0.3-3.0 μg·mL-1,Y=0.093 6X-0.017 3(r=0.999 6),and 0.3-3.0 μg·mL-1,Y=0.086 6X-0.022 3(r=0.999 1) respectively.The lowest limit of quantitation were both 0.05 μg·mL-1(S/N>3),and the ingredients showed good relationships between the peak area and the concentration.Sample reproducibility was good because the test sample was stable in 5 h.The extraction rates of bupivacaine hydrochloride by 10%,20%,30% fat emulsion were 46.0%,70. 4%,89.2% respectively.The extraction rates of ropivacaine hydrochloride by 10%,20%,30% fat emulsion were 51.3%,71.6%, 90.7% respectively. Conclusion Electric potential and the pH value of the 10%,20%,30% fat emulsion are similar,while the particle size increase slightly.Free bupivacaine hydrochloride and ropivacaine hydrochloride can be absorbed and with the increase of fat content,the extraction of local anesthetic is increased.The mechanism of action of fat for the treatment of local anesthetic toxicity maybe related to that fat emulsions can provided lipid,so that the excessive local anesthetic or those which had already distributesd in tissue can re-dispersed in lipid,and then the plasma concentration of local anesthetic is reduced,the toxicity is also reduced.