The Pharmacodynamic Effects of a Lower-Lipid Emulsion of Propofol: A Comparison with the Standard Propofol Emulsion Dajun Song, MD, PhD, Mohamed Hamza, MD, Paul F. White, PhD, MD, Kevin Klein, MD, Alejandro Recart, MD, and Omeed Khodaparast, MS From the Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas Using a randomized, double-blind protocol design, we compared a new lower-lipid emulsion of propofol (Ampofol ® ) containing propofol 1%, soybean oil 5%, and egg lecithin 0.6% with the most commonly used formulation of propofol (Diprivan ® ) with respect to onset of action and recovery profiles, as well as intra- operative efficacy, when administered for induction and maintenance of general anesthesia as part of a “balanced” anesthetic technique in 63 healthy outpa- tients. Anesthesia was induced with sufentanil 0.1 g/kg (or fentanyl 1 g/kg) and propofol 2 mg/kg IV and maintained with a variable-rate propofol infu- sion, 120 –200 g · kg -1 · min -1 . Onset times to loss of the eyelash reflex and dropping a syringe were re- corded. Severity of pain on injection, speed of induc- tion, intraoperative hemodynamic variables, and electroencephalographic bispectral index values were assessed. Recovery times to opening eyes and orientation were noted. The results demonstrated that there were no significant differences between Ampofol ® and Diprivan ® with respect to onset times, speed of induction, anesthetic dose requirements, bispectral index values, hemodynamic variables, re- covery variables, or patient satisfaction. However, the incidence of pain on injection was more frequent in the Ampofol ® group (26% versus 6%, P  0.05). We conclude that Ampofol ® is equipotent to Diprivan ® with respect to its anesthetic properties but was asso- ciated with a more frequent incidence of mild pain on injection. (Anesth Analg 2004;98:687–91) P ropofol is the most commonly used IV anesthetic (1). Although propofol has an excellent recovery profile (e.g., fast and smooth emergence, infre- quent incidence of postoperative nausea and vomit- ing), its use is associated with pain on injection, in- creased triglyceride levels, and the potential for microbial contamination (2–5). In recent years, efforts have been made to find alternative formulations of propofol that might minimize some of these adverse effects (6 – 8). Ampofol ® (Amphastar Pharmaceuticals, Inc., Rancho Cucamonga, CA) is a new propofol formu- lation that contains 50% less soybean oil and egg lecithin emulsion than the currently marketed formulations of propofol, Diprivan ® (AstraZeneca, Wilmington, DE) and generic propofol (Gensia Sicor, Irvine, CA). Ampofol ® contains 1% propofol, 5% soybean oil, and 0.6% egg lecithin. In addition, Ampofol ® pos- sesses intrinsic antimicrobial activity (9). Therefore, in contrast to Diprivan ® and generic propofol, it does not require a preservative or microbial growth retardant. There have been no clinical studies comparing the pharmacodynamic profile of Ampofol ® to the cur- rently available propofol formulations. We hypothesized that Ampofol ® (1% propofol) would have a similar pharmacodynamic profile to the current “gold standard” propofol formulation (Diprivan ® ), which contains 1% propofol in 10% soybean oil and 1.2% egg lecithin. This randomized, double-blind study was de- signed to evaluate the comparability of these two propofol formulations when used as part of a “balanced” anesthetic technique to induce and maintain general anesthesia in outpatients undergoing elective surgery. Methods After obtaining IRB approval and written informed consent, 65 ASA physical status I or II outpatients Supported, in part, by a research grant from Amphastar Pharma- ceuticals, Inc. (Rancho Cucamonga, California) and endowment funds from the Margaret Milam McDermott Distinguished Chair in Anesthesiology. Accepted for publication October 8, 2003. Address correspondence and reprint requests to Dr. Paul F. White, Professor and McDermott Chair of Anesthesiology, Depart- ment of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas, 5161 Harry Hines Boule- vard, CS 2. 282, Dallas, TX 75390 –9068. Address email to paul.white@utsouthwestern.edu. DOI: 10.1213/01.ANE.0000103184.36451.D7 ©2004 by the International Anesthesia Research Society 0003-2999/04 Anesth Analg 2004;98:687–91 687