Domperidone is a potent gastrokinetic agent and antinauseant currently undergoing clinical trials in the United States. The bioequivalence of 20 mg of domperidone given as free-base tablets and maleate salt tablets, and the bioavailability of base and maleate tablets relative to a solution, were studied in 21 fasting men using a crossover design. Plasma samples collected for up to 48 hours were analyzed for domperidone levels, using a sensitive and specific radioimmunoassay (RIA). The absorption of domperidone was very rapid, with mean peak plasma concentration (Cmax) values of 18.8, 15.0, and 20.7 ng/mL attained at 0.9, 1.2, and 0.6 hours after the administration of base tablet, maleate tablet, and solution, respectively. The mean elimination half-life (t1/2) ranged from 12.6 to 16.0 hours. The mean oral clearance (CL/F) after the solution dose was 4,735 +/- 2,017 mL/min and the mean apparent volume of distribution (Vd/F) was 6,272 +/- 5,100 L, indicating an extensive distribution of domperidone in the body. The area under the plasma concentration-time curve (AUC) data demonstrated bioequivalence of base and maleate tablets. The relative bioavailability for base tablet and maleate tablet was 107 +/- 50% and 116 +/- 47%, respectively, of that of the solution. Dose proportionality of domperidone was also studied in 12 subjects at solution doses of 10, 20, and 40 mg. Linear correlations between the dose and Cmax and AUC values were observed. Mean CL/F remained relatively constant after doses of 10, 20, and 40 mg (5,255 +/- 3,159, 4,842 +/- 1,774, and 4,380 +/- 1,289 mL/min, respectively), indicating linear pharmacokinetics of domperidone over the dose range studied.

Adult↗

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Food interaction and steady-state pharmacokinetics of itraconazole oral solution in healthy volunteers.

STUDY OBJECTIVES: To evaluate the effect of food on the bioavailability of itraconazole (ITR) hydroxypropyl-beta-cyclodextrin (HP-beta-CD) solution under multiple-dose to steady-state conditions, and to determine the pharmacokinetics of ITR solution at steady state. DESIGN: Open-label, randomized, multiple-dose, crossover study SETTING: University-affiliated health center. PATIENTS: Thirty healthy men randomized to one of two treatment sequences (fasted-fed, fed-fasted). INTERVENTIONS: Subjects were either fasted or fed a standard breakfast before receiving ITR oral solution 200 mg once/day for 15 days. Crossover phases were separated by a 4-week washout period. MEASUREMENTS AND MAIN RESULTS: On day 1, blood samples were collected before the dose (time zero) and 0.5, 1, 2, 3, 4, 5, 6, 8, 12, and 24 hours after the dose. Trough samples were obtained before the dose on days 4, 7, 12, 13, and 14. On day 15, samples were obtained at the same times as day 1, and at 36, 48, 72, 96, 168, 240, and 360 hours. Samples were analyzed by high-performance liquid chromatography for ITR and its major metabolite hydroxyitraconazole (OH-ITR). Urine was collected on days 1 and 15 before and 0-8 and 8-24 hours after the dose; HP-beta-CD was measured by size-exclusion chromatography. Mean bioavailabilities of ITR and OH-ITR were 43% and 38% higher, respectively, when ITR solution was taken as a single dose under fasted conditions. With multiple dosing, steady state was achieved by day 14. At steady state, mean bioavailabilities were 29% and 17% higher, respectively, in the fasted state; terminal half-life was similar under fasted and fed conditions (mean 39.8 and 37.5 hrs for ITR, respectively; 27.3 and 26.2 hrs for OH-ITR, respectively). HP-beta-CD was eliminated almost exclusively in urine. CONCLUSION: The bioavailability of ITR and OH-ITR is enhanced when ITR oral solution is given in the fasted state; this was true for both single and multiple dosing to steady state.

2-Hydroxypropyl-beta-cyclodextrin↗