1.
Relative bioavailability of lisdexamfetamine 70-mg capsules in fasted and fed healthy adult volunteers and in solution: a single-dose, crossover pharmacokinetic study.
Krishnan, S, Zhang, Y
Journal of clinical pharmacology. 2008;(3):293-302
Abstract
The relative bioavailability of oral lisdexamfetamine dimesylate, a prodrug of d-amphetamine, and active d-amphetamine was assessed in an open-label, single-dose, 3-treatment, 3-period, randomized, crossover study in 18 healthy adult volunteers. Following a fast of at least 10 hours, subjects were administered an intact capsule of 70 mg lisdexamfetamine, a solution containing the capsule contents, or an intact capsule with a high-fat meal. Standard meals started 4 hours following lisdexamfetamine administration. Blood samples were taken predose (0 hours) and 0.5 to 72 hours postdose, and the concentrations of d-amphetamine and lisdexamfetamine were measured. AUC and C(max) for d-amphetamine were similar when lisdexamfetamine 70 mg was administered to healthy adults in the fed or fasted state. The AUC of intact lisdexamfetamine was similar when the latter was taken without food or in solution, but C(max) was lower when lisdexamfetamine was administered with food. The t(max) of d-amphetamine and intact lisdexamfetamine was similar when taken in solution or in the fasted state but was about 1 hour longer when taken with food. Adverse events were typical for amphetamine products. These findings indicate that food does not have a significant effect on d-amphetamine or lisdexamfetamine bioavailability in healthy adults and that lisdexamfetamine was well tolerated.
2.
SLI381 (Adderall XR), a two-component, extended-release formulation of mixed amphetamine salts: bioavailability of three test formulations and comparison of fasted, fed, and sprinkled administration.
Tulloch, SJ, Zhang, Y, McLean, A, Wolf, KN
Pharmacotherapy. 2002;(11):1405-15
Abstract
STUDY OBJECTIVES To assess the bioavailability of three test formulations of a single dose of extended-release Adderall 20-mg capsules compared with two doses of immediate-release Adderall 10-mg tablets, and to assess the bioequivalence of a single 30-mg dose of the chosen extended-release Adderall formulation (designated as SLI381) administered in applesauce (sprinkled) and the same dose administered as an intact capsule with or without food. DESIGN Randomized, open-label, crossover study. SETTING Clinical research unit. PATIENTS Forty-one healthy adults. INTERVENTIONS Study A had four treatment sequences: three test formulations (A, B, and C) of a single dose of extended-release Adderall 20 mg, and two 10-mg doses of Adderall given 4 hours apart. Study B had three treatment sequences: a single dose of SLI381 30 mg as an intact capsule after overnight fast, an intact capsule after a high-fat breakfast, and the contents of a capsule sprinkled in 1 tablespoon of applesauce. MEASUREMENTS AND MAIN RESULTS The 20-mg test formulation A had comparable pharmacokinetic profiles and bioequivalence in rate and extent of drug absorption to Adderall 10 mg twice/day for both d- and l-amphetamine. Formulations B and C had statistically significant differences from the reference drug in some pharmacokinetic parameters. A 30-mg dose of SLI381 showed no significant differences in rate and extent of absorption of d- and l-amphetamine for fasted or sprinkled conditions compared with the high-fat meal condition. CONCLUSION SLI381 20 mg/day is bioequivalent to Adderall 10 mg twice/day. SLI381 30 mg administered in applesauce is bioequivalent in terms of both rate and extent of absorption to the same dose administered as an intact capsule in both fasted and fed states.
3.
Multiple dose pharmacokinetics of fiduxosin under fasting conditions in healthy elderly male subjects.
Dutta, S, Zhang, Y, Daszkowski, DJ, Granneman, GR, Verlinden, M
The Journal of pharmacy and pharmacology. 2002;(5):641-7
Abstract
Selective alpha1a-adrenoceptor antagonists are effective agents for treatment of benign prostatic hyperplasia, a disorder occurring in middle-aged and elderly males. The objective of this study was to determine the pharmacokinetics of fiduxosin, a novel alpha1a-adrenoceptor antagonist, following multiple dose administration. This was carried out in a Phase I, randomized, double-blind, placebo-controlled, parallel group, multiple oral dose study of fiduxosin. Single once-daily oral doses of 30, 60, 90 or 120 mg of fiduxosin or placebo were administered to healthy elderly male subjects (n = 48; 8 active and 4 placebo per dosing group) for 14 consecutive days. Fiduxosin plasma concentration-versus-time profiles for days 1, 7 and 14 were used to assess fiduxosin pharmacokinetics. Steady state was achieved by day 7. At steady-state mean Tmax (time to maximum plasma concentration), CL/F (apparent oral clearance) and Vbeta/F (apparent volume of distribution) ranges were 1.8-7.8 h, 27.3-47.2 L h(-1) and 846-1399 L, respectively. Tmax and VbetaF were independent of dose. Cmax (maximum plasma concentration), Cmin (minimum plasma concentration) and AUC24 (area under plasma concentration vs time curve from 0 to 24 h) for days 7 and 14 were linearly proportional with dose overthe 30-120 mg/day dose range and were unchanged from day 7 to day 14. It was concluded that fiduxosin multiple-dose pharmacokinetics were dose-independent and time-invariant over the 30-120 mg/day dose range under fasting conditions.
4.
Effect of food on the pharmacokinetics of fiduxosin in healthy male subjects.
Dutta, S, Zhang, Y, Granneman, GR, Verlinden, M
European journal of drug metabolism and pharmacokinetics. 2002;(1):49-52
Abstract
The effect of food on the pharmacokinetics of fiduxosin, a novel selective alpha1a-receptor antagonist, was determined in healthy male subjects. This was a Phase I, open-label, single-center, randomized, two-period, crossover, single oral dose study of fiduxosin. Healthy male subjects (N= 14) were administered single oral doses of 30 mg of fiduxosin under fasting or nonfasting (1026 Kcal, 54 g fat, 46% calories from fat) conditions in each period. Fiduxosin plasma concentration profiles were used to assess fiduxosin pharmacokinetics. The mean Cmax, Tmax, AUC(infinity), CL/F and Vbeta/F values under fasting and nonfasting conditions were 34.3 and 150 ng/mL, 5.4 and 5.4 h, 822 and 1940 ng x h/mL, 42.5 and 17.2 L/h, and 924 and 235 L, respectively. The harmonic mean t 1/2 under fasting and nonfasting conditions were 13.9 and 9.28 h, respectively. Food significantly increased the bioavailability of fiduxosin. Under the nonfasting regimen, the Cmax central value was more than 4-fold and the AUC(infinity) central value more than 2-fold the central value of the fasting regimen. Tmax was not significantly different between fasting and nonfasting regimens. Food also decreased fiduxosin oral clearance (CL/F) by 60% and volume of distribution (Vbeta/F) by 75%.