A PK/PD Study of Fospropofol Disodium Compared With Propofol Injectable Emulsion

AUC(0-inf) is a measure of drug concentration equal to the area under the plasma concentration-time profile from time 0 to infinity. An arterial line (A-line) and venous line (V-line) were placed prior to dosing during each treatment period and used to collect blood samples for plasma concentration measurements at specific time points. Plasma arterial and venous concentrations of fospropofol were quantified by high-performance liquid chromatography with mass spectrometric detection (LC-MS/MS). The AUC(0-inf) was calculated from the sum of AUC from time 0 to time t (AUC(0-t)) and the residual area calculated as Ct/λz, where Ct was the observed concentration at last quantifiable concentration and λz was the terminal elimination rate constant. The plasma concentrations from the venous sampling were descriptively compared head-to-head with the arterial sampling.

An A-line and V-line were placed prior to dosing during each treatment period and used to collect blood samples for plasma concentration measurements at specific time points. Plasma arterial and venous concentrations of propofol were quantified by high-performance liquid chromatography with mass spectrometric detection (LC-MS/MS). The AUC(0-inf) was calculated from the sum of AUC(0-t) and the residual area calculated as Ct/λz, where Ct was the observed concentration at last quantifiable concentration and λz was the terminal elimination rate constant. The plasma concentrations from the venous sampling were descriptively compared head-to-head with the arterial sampling. In addition, the arterial plasma concentrations of fospropofol, propofol liberated from fospropofol, and propofol delivered from propofol injectable emulsion were used to refine the population PK model developed previously.

Arterial and venous blood samples were collected and analyzed for fospropofol concentrations as described previously. AUC(0-t) was calculated using the log-linear trapezoidal rule (linear trapezoidal rule up to maximum observed plasma concentration (Cmax), log trapezoidal rule following Cmax) from time of dosing to the last quantifiable concentration. The plasma concentrations from the venous sampling were descriptively compared head-to-head with the arterial sampling.

Arterial and venous blood samples were collected and analyzed for propofol concentrations as described previously. AUC(0-t) was calculated using the log-linear trapezoidal rule (linear trapezoidal rule up to Cmax, log trapezoidal rule following Cmax) from time of dosing to the last quantifiable concentration. The plasma concentrations from the venous sampling were descriptively compared head-to-head with the arterial sampling. In addition, the arterial plasma concentrations of fospropofol, propofol liberated from fospropofol, and propofol delivered from propofol injectable emulsion were used to refine the population PK model developed previously.

Arterial and venous blood samples were collected and analyzed for fospropofol concentrations as described previously. Cmax was the highest plasma drug concentration observed over the entire sampling period, and was obtained directly from the experimental plasma concentration time data without interpolation. The plasma concentrations from the venous sampling were descriptively compared head-to-head with the arterial sampling.

Arterial and venous blood samples were collected and analyzed for propofol concentrations as described previously. Cmax was the highest plasma drug concentration observed over the entire sampling period, and was obtained directly from the experimental plasma concentration time data without interpolation. The plasma concentrations from the venous sampling were descriptively compared head-to-head with the arterial sampling.

Pharmacodynamic (PD) effects were obtained from continuous BIS score recordings obtained throughout the study and from clinical assessment of sedation using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale. The BIS measurements continued until the participant was fully recovered in the opinion of the investigator or until the PD effect measure returned to baseline. The BIS score varied between 100 (associated with being fully awake) and 0 (associated with a flat line on the electroencephalogram (EEG)). The BIS Index was described by the maximal effect (Emax) model.

PD effects were determined from continuous BIS score recordings and from clinical assessment of sedation using the MOAA/S scale. The MOAA/S scale was used to rate the level of alertness/sedation from a score of 0 (does not respond to painful stimulus) to 5 (alert) in the category of responsiveness, with 5 being the MOAA/S value for a fully awake adult. Time to sedation was defined as the time from the first dose of study medication to the first two consecutive MOAA/S scores less than or equal to 4. Fully awake status was reached at the first of 3 consecutive MOAA/S scores of 5 measured every 2 minutes after study drug administration. The MOAA/S scale was described by the Emax model.

The PK parameters for propofol from propofol injectable emulsion were used as the reference formulation. Because propofol is a metabolite of fospropofol, all calculations were conducted after correcting for the different molecular weights of these formulations. Molecular weights of 332.24 (288.24 for free base) and 178.27 were used for fospropofol disodium and propofol injectable emulsion, respectively. The propofol parameters were adjusted as appropriate as discussed above and natural log transformed prior to comparison. Relative bioavailability of propofol from fospropofol disodium (E2083) to propofol from propofol injectable emulsion is calculated as (AUC(FP) x Total Dose of Propofol/AUC(P) x Total Dose of E2083) x Molecular fraction, where AUC(FP) is AUC(0-t) or AUC(0-inf) of propofol from E2083, AUC(P) is AUC(0-t) or AUC(0-inf) of propofol from propofol injectable emulsion and molecular fraction is molecular weight of propofol (178.27)/E2083 (332.24).