Pharmacodynamics of two different propofol formulations

Background. Propofol is nowadays available in various lipid formulations. We compared two different propofol formulations with respect to pharmacodynamics, using the EEG and clinical signs. Materials and methods. Ten volunteers received Diprivan((R)) 1% and Propofol 1% MCT Fresenius((R)) as a computer controlled infusion with increasing propofol target concentrations. A sigmoid E-max model with effect compartment was estimated for the median frequency of the EEG power spectrum, based on measured arterial propofol plasma concentrations. Clinical pharmacodynamics were assessed by reaction on acoustic stimuli, eyelid reflex and corneal reflex. Results. The drugs did not differ in pharmacodynamics with respect to EEG (EC50 2.1 +/- 0.6 for Diprivan and 2.1 +/- 0.5 mu g/ml for Propofol Fresenius) and clinical signs. The pharmacodynamic model was characterized by a steep concentration effect relationship and a distinct hysteresis between propofol plasma concentration and effect (k(e0) 0.12 +/- 0.04 and 0.12 +/- 0.5 min(-1)). Conclusions. The investigated lipid formulations have no influence on the pharmacodynamics of propofol.