Objective: Current extended-release (ER) formulations of psychostimulants used for treatment of attention-deficit/hyperactivity disorder (ADHD) provide an extended duration of ADHD symptom control; however, the onset of efficacy can be protracted and variable, leaving the early morning untreated. The primary objective was to characterize the single-dose pharmacokinetics and tolerability of HLD200, an evening-dosed, delayed-release (DR) and ER formulation of methylphenidate (MPH), in healthy adults and in adolescents and children with ADHD.Methods: The pharmacokinetics and tolerability of a single, oral evening dose of HLD200 (54 mg) were evaluated in two single-center open-label studies: the first in healthy adults (n = 12) and the second in adolescents (n = 18) and children (n = 11) with ADHD. Primary pharmacokinetic endpoints were the rate and extent of MPH absorption (Cmax and area under the curve [AUC]) and time to peak concentration (Tmax). These parameters were calculated using noncompartmental analysis.Results: HLD200 produced a pharmacokinetic profile characterized by an 8- to 10-hour delay in MPH release, followed by a period of extended controlled release, resulting in an ascending absorption profile that coincided with the early morning and afternoon. Mean values (coefficient of variation [CV]%) of weight-adjusted pharmacokinetic parameters were similar in adults and in adolescents and children with ADHD: Cmax ([ng/mL]/[mg/kg]) was 9.1 (35.2), 8.8 (34.5), and 7.4 (30.1); AUC0–t ([ng · h/mL]/[mg/kg]) was 126.5 (35.5), 129.4 (34.8), and 129.7 (27.3); and Tmax (hours) was 15.6 (11.1), 17.1 (14.5), and 17.7 (14.1), respectively. Intersubject variability in the mean time to achieve ascending plasma MPH concentrations of 2, 3, 4, and 5 ng/mL was low (CV: 7.8%–17.7%).Conclusions: Evening-dosed HLD200 produces the intended DR and ER pharmacokinetic profile that provides a consistent predictable delay in initial MPH release until the early morning, followed by extended release across the day. The body weight-adjusted pharmacokinetics of HLD200 were similar between adults and adolescents and children with ADHD.

Objectives: HLD200, an oral, once-daily, evening-dosed, delayed-release, and extended-release methylphenidate (DR/ER-MPH), was designed to provide efficacy from the early morning, throughout the day, and into the evening to individuals with attention-deficit/hyperactivity disorder. The objectives were to evaluate DR/ER-MPH pharmacokinetic (PK) properties in healthy adults, including dose proportionality, food effect, the potential of accumulation using multiple-dose modeling, and bioavailability compared to an immediate-release MPH (IR MPH). Methods: Three open-label, single-dose, crossover studies were conducted, all with a 7-day washout between treatments. In Study I, 20 subjects received evening-dosed DR/ER-MPH (20 and 100 mg) followed by a medium-fat breakfast; 13 subjects received a subsequent 100-mg dose of DR/ER-MPH followed by a low-fat breakfast. In Study II, 18 subjects were evaluated after receiving evening-dosed DR/ER-MPH (100 mg) under 3 conditions: immediately after a high-fat meal, sprinkled on applesauce, and in a fasted state. In Study III, 11 and 12 subjects received evening-dosed DR/ER-MPH (100 mg) and morning-dosed IR MPH (20 mg), respectively. Results: DR/ER-MPH demonstrated dose proportionality between 20- and 100-mg doses. DR/ER-MPH PK parameters were not significantly affected by breakfast content or by sprinkling capsule contents. A high-fat meal immediately preceding evening dosing did not affect total MPH exposure but lowered peak MPH exposure by 14% and 11% versus fasted and sprinkled states, and time to peak exposure was delayed by ∼2.5 hours; these PK differences are unlikely to be clinically significant. Based on multiple-dose simulations using data from Study I, negligible accumulation of DR/ER-MPH was predicted. The relative bioavailability for DR/ER-MPH compared to IR MPH was 73.9%. No serious adverse events (AEs) were reported, and the observed AEs were consistent with MPH. There were no discontinuations in Studies I and III, but three participants withdrew in Study II due to AEs. Conclusions: Evening-dosed DR/ER-MPH demonstrated dose proportionality and can be administered with or without food. Significant accumulation is unlikely with multiple dosing.

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.

In humans, the plasma enzyme butyrylcholinesterase, BChE (EC 3.1.1.8), mediates the in vivo plasma hydrolysis of cocaine to the pharmacologically inactive metabolite ecgonine methyl ester, EME. This enzyme has been purified from human plasma to investigate the potential as a treatment for cocaine intoxication. Cocaine (2.1 μg mL−1) was incubated in plasma with a BChE concentration in the normal range (3.02 μg mL−1) and in plasma with enhanced BChE concentrations of 9.14, 20.8 and 37.8 μg mL−1, respectively for time periods up to 120 min. Cocaine and the hydrolytic products, ecgonine methyl ester and ecgonine, were quantified simultaneously by gas chromatography‐mass spectrometry (GC‐MS). The enhancement of plasma BChE concentration resulted in a dramatic increase in the rate of hydrolysis of cocaine. There was a stoichimetric conversion of cocaine to the inactive hydrolysis product, ecgonine methyl ester. Accordingly, the half‐life of cocaine in plasma decreased significantly with enhanced BChE concentration. At plasma BChE concentrations of 3.02, 9.14, 20.8 and 37.8 μg mL−1, half‐life values of 116, 35.8, 21.4 and 9.0 min, respectively were observed. The marked reduction in cocaine half‐life provides evidence supporting the potential therapeutic use of BChE for the treatment of cocaine intoxication. © 1998 John Wiley & Sons, Ltd.

Carbatrol, a new dosage form of carbamazepine (CBZ), was developed consisting of three different types of pellets (immediate release, controlled release, and enteric release). The objective of this study was to explore the influence of food on absorption of CBZ. This was a randomized, open-label, single-dose crossover study conducted in 12 healthy volunteers. Treatments were 2 x 200 mg Carbatrol with a high-fat meal, fasted, or sprinkled over applesauce (but otherwise fasted). Each subject received one dose of each treatment separated by a washout period of at least 2 weeks. CBZ bioequivalence was established based on the equivalence of AUC (extent of absorption) in all three conditions. Carbatrol may be taken with or without food or the capsule opened and sprinkled on food.