The chromatographic separation was achieved

on a ChiralPak AD-H, 4.60 × 150 mm, 5 μm LC–MS column, with a mobile phase. The mass spectrometer was operated in positive mode, and HDAC phosphorylation the resolution setting used was unit for both Q1 and Q3. The MRM transition was m/z 234 → 84 for MPH, and the MRM transition was m/z 243 → 93 for the internal standard, MPH-D9. The assay ranges were from 0.05 to 50 ng/mL for guanfacine analysis, based on a plasma sample volume of 200 μL, and from 0.25 to 100 ng/mL for d-MPH and l-MPH analysis, based on a plasma sample volume of 100 μL. Safety was evaluated by collecting data on reported AEs, physical examination findings, vital signs, and 12-lead ECGs. At the end of each treatment period, biochemical and hematologic assessments were performed and urinalysis was conducted. Staff contacted subjects 7 days after the last dose of the last investigational agent to collect data on new-onset AEs and other treatment-related concerns. 2.4 Statistical Methods The primary

analysis was the pharmacokinetic analysis performed using data from the pharmacokinetic 5-Fluoracil cell line population. This population consisted of all subjects who received at least one dose of study medication, had at least one postdose safety assessment, and had evaluable concentration–time profiles for guanfacine, d-MPH, or l-MPH. Pharmacokinetic parameters were determined from the plasma concentration–time data by noncompartmental analysis and included Cmax, time to Cmax (tmax), AUCt, AUC∞, apparent elimination half-life (t½), apparent oral-dose clearance (CL/F), and apparent volume of distribution during the terminal phase after oral administration (Vλz/F). CL/F and Vλz/F were corrected for bodyweight. Summary statistics, including

Tangeritin the numbers of observations, means, standard deviations (SDs), medians, maximums, minimums, and geometric means, were determined for all pharmacokinetic parameters for all treatment regimens. The means of the log-transformed pharmacokinetic parameters were compared among (between) treatments, using an analysis of variance (ANOVA) with sequence, period, and treatment as fixed effects, and subject nested within sequence as a random effect for a crossover study design. To estimate the magnitude of the treatment differences in Cmax and AUC∞, the geometric mean ratio (GMR, defined as the least squares mean difference in the log-transformed parameters back-transformed to the original scale) and their 90 % confidence intervals (CIs) were also calculated. The hypothesis of a drug interaction of GXR and MPH would be rejected if either of the following were to fall within the interval of 0.80–1.25: (i) the 90 % CIs of the GMR of guanfacine following GXR alone to guanfacine following GXR in combination with MPH; or (ii) the 90 % CIs of the GMR of d-MPH following MPH alone to d-MPH following MPH in combination with GXR.