Phoenix 8

Non-compartmental pharmacokinetics analysis was performed on Phoenix^® 8.2 (Certara Corporation, Mountain View, CA, USA) to determine plasma pharmacokinetic parameter of MP1 in plasma. Peak plasma concentration (C_max) and time for the peak plasma concentration (T_max) was obtained from visual inspection of the concentration-time plot. The area under the curve (AUC_0–∞) was estimated using the linear trapezoidal method from 0–t_last and extrapolation from last time point to infinity based on the observed concentration at the last time point divided by the terminal elimination rate constant (k).
The elimination half-life (t_1/2) was calculated using Equation (12). Clearance (CL) was calculated using Equation (13) and the apparent volume of distribution of the elimination phase (V_d) were calculated using Equation (14). The tissue to blood (Kp) ratio was calculated by using Equation (15).
${\mathrm{t}}_{1/2}=\frac{0.693}{\mathrm{k}}$
$\mathrm{CL}=\frac{\mathrm{Dose} \left(\frac{\mathrm{mg}}{\mathrm{kg}}\right)}{{\mathrm{AUC}}_{0–\infty }}$
${\mathrm{V}}_{\mathrm{d}}=\frac{\mathrm{Dose} \left(\frac{\mathrm{mg}}{\mathrm{kg}}\right)}{{\mathrm{K}\ast \mathrm{AUC}}_{0–\infty }}$
${\mathrm{K}}_{\mathrm{P}}=\frac{\mathrm{Concentration} \mathrm{in} \mathrm{Tissue}}{\mathrm{Concentration} \mathrm{in} \mathrm{Blood}}$

Pharmacokinetic analysis for repeated dosing was performed on each HEMP animal to determine the pharmacokinetics of CBDA using non-compartmental methods using computer software (Phoenix 8.2, Certara, Inc., Princeton, NJ, USA) using methods similar to Kleinhenz et al.^{22 (link)}. Relevant pharmacokinetic parameters are defined and reported in Table 2.

Non-compartmental analysis was performed on the plasma concentration-time profiles using Phoenix 8.4 (Certara LP, NJ, USA). All dosing groups were included in the analysis, except for the IR administration data because of the low plasma concentrations (around LOQ). The following pharmacokinetic parameters were calculated: area under the plasma concentration-time curve, from 0 to infinity (AUC_0−inf); maximal plasma concentration (C_max) and time to maximal plasma concentration (T_max); terminal elimination half-life; elimination rate constant and mean residence time. Total body clearance and volume of distribution after IN and PO administration were not corrected for their respective bioavailabilities. The relative bioavailability of the IN administration when compared with the commercial oral product was calculated according to the following formula:
Due to the dose discrepancy between the PO and IR administration (100 mg) and the IN administration (20 mg) and to facilitate comparison of the systemic exposure between the administration routes, the AUC and C_max of PO/IR and IN were normalized for dose by dividing by 100 and 20, respectively.

Plasma concentration-time profiles were modelled by non-compartmental analysis (NCA) using Phoenix 8.4 (Certara, NJ, USA). Plasma concentrations measured at 360 and 480 min after ketamine administration fell below the LOQ and were therefore not taken into account for pharmacokinetic analysis. The following major pharmacokinetic parameters were calculated: AUC_0-4h area under the plasma concentration-time curve from 0 to 4 hours post-administration; AUC_0-∞ area under the plasma concentration-time curve from 0 to infinity; C_max maximal plasma concentration (IN); C₀ plasma concentration at time zero (IV); T_max time to maximal plasma concentration (IN); Vd volume of distribution; Cl total body clearance; T_1/2el terminal elimination half-life; k_el elimination rate constant. Vd and Cl values after IN administration were not corrected for IN bioavailability (F). The absolute IN F, expressed as percentage, was calculated according to the following formula:
$\mathrm{F}=\mathrm{A}\mathrm{U}{\mathrm{C}}_{0\mathrm{‐}\mathrm{i}\mathrm{n}\mathrm{f}}\mathrm{I}\mathrm{N}/\mathrm{A}\mathrm{U}{\mathrm{C}}_{0\mathrm{‐}\mathrm{i}\mathrm{n}\mathrm{f}}\mathrm{I}\mathrm{V}\mathrm{*}100.$