title: The Effect of Lipid Emulsion on Pharmacokinetics of Bupivacaine in Rats: Long-Chain Triglyceride Versus Long- and Medium-Chain Triglyceride.
abstract: Lipid infusions have been proposed to treat local anesthetic-induced cardiac toxicity. This study compared the effects of long-chain triglyceride (LCT) emulsions with those of long- and medium-chain triglyceride (LCT/MCT) emulsions on the pharmacokinetics of bupivacaine in a rat model.
  
  
  
  After administration of intravenous infusion of bupivacaine at 2 mg·kg·min for 5 minutes in Sprague-Dawley (SD) rats, either Intralipid 20%, an LCT emulsion (LCT group, n = 6), or Lipovenoes 20%, an LCT/MCT emulsion (LCT/MCT group, n = 6), was infused at 2mg·kg·min for 5 minutes. The concentrations of total plasma bupivacaine and bupivacaine that were not bound by lipid (lipid unbound) were measured by a liquid chromatography-tandem mass spectrometric method. A 2-compartmental analysis was performed to calculate the lipid-bound percentage of bupivacaine and its pharmacokinetics.
  
  
  
  In the LCT group, the clearance (15 ± 2 vs 10 ± 1 mL·min·kg, P = .003) was higher; the volume of distribution (0.57 ± 0.10 vs 0.36 ± 0.11 L·kg, P = .007) and K21 (0.0100 ± 0.0018 vs 0.0070 ± 0.0020 min, P = .021, P' = .032) were larger; and the area under the blood concentration-time curve 0 - t; (605 ± 82 vs 867 ± 110 mgL·min, P =.001) and the area under the blood concentration-time curve (0 - ∞) (697 ± 111 vs 991 ± 121 mgL·min, P =.001) were less, when compared with the LCT/MCT group.
  
  
  
  LCT emulsions are more effective than LCT/MCT emulsions in the metabolism of bupivacaine through demonstration of a superior pharmacokinetic profile.
authors.affiliation: From the Department of Anesthesiology, The First Affiliated Hospital, Wenzhou Medical University, Zhejiang, China.
authors.forename: Wan
authors.initials: W
authors.lastname: Tang
authors.forename: Quanguang
authors.initials: Q
authors.lastname: Wang
authors.forename: Kejian
authors.initials: K
authors.lastname: Shi
authors.forename: Jiaojiao
authors.initials: J
authors.lastname: Dong
authors.forename: Shengxian
authors.initials: S
authors.lastname: Lin
authors.forename: Shishi
authors.initials: S
authors.lastname: Zhao
authors.forename: Cong
authors.initials: C
authors.lastname: Wu
authors.forename: Yun
authors.initials: Y
authors.lastname: Xia
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Papadimos
authors.forename: Xuzhong
authors.initials: X
authors.lastname: Xu
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D004655:Emulsions / Q000008:administration & dosage / Q000493:pharmacokinetics; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage / Q000493:pharmacokinetics*; D007262:Infusions, Intravenous; D010743:Phospholipids / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D013024:Soybean Oil / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D014280:Triglycerides / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000779:Anesthetics, Local; D004655:Emulsions; D005217:Fat Emulsions, Intravenous; D010743:Phospholipids; D014280:Triglycerides; C545823:soybean oil, phospholipid emulsion; D013024:Soybean Oil; D002045:Bupivacaine