This study was designed to assess the pharmacokinetic effects of a single dose of HLD200 (methylphenidate hydrochloride) in children and adolescents with ADHD.

This study utilized a single-center, open-label, single-treatment, fasted design to examine the rate and extent of absorption of evening-administered HLD200 in children (6-12 years) and adolescents (13-17 years) with ADHD.

Following a screening period that included five days washout to allow for clearance of any prior ADHD medications, subjects were domiciled in-clinic and administered HLD200 (B-formulation; 54 mg; oral capsule) at 9 pm under fasted conditions. Subjects were then observed for safety and tolerability and a total of 18 blood samples collected during a 48 hour period (at t=0, 4, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 20, 22, 24, 36 and 48 hours post-dosing). These samples were then assayed for methylphenidate plasma concentrations and this data used for calculation of pharmacokinetic parameters.

Inclusion Criteria:

• Male and female adolescents (13-17 years) and children (6-12 years).
• Previous diagnosis of ADHD and confirmation using the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID).
• ADHD symptoms controlled on a stable dose of ADHD medication. Subjects should be on MPH or have previous history of symptom control during treatment with MPH.
• Physical examination free of clinically significant findings, unless deemed NCS by the Investigator and Medical Monitor;
• Able to swallow treatment capsules;
• Available for entire study period;
• Provision of informed consent (from the parent[s] and/or legal representative[s]) and assent (from the subject); and
• Female subjects of childbearing potential (i.e., post-menarche) required to have a negative result on urine pregnancy testing (and will be given specific instructions on avoiding pregnancy during trial)

Exclusion Criteria:

• Any known history or presence of significant cardiovascular, pulmonary, hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic, dermatologic, neurologic, ophthalmologic disease, unless deemed NCS by the Investigator and the Medical Monitor;
• Presence of any significant physical or organ abnormality;
• Any illness during the 4 weeks before this study, unless deemed NCS by the Investigator and the Clinical and/or Medical Monitor;
• Severe comorbid psychiatric diagnosis that may affect subject safety or confound results (e.g., psychosis, bipolar disorder);
• Known history of moderate to severe asthma;
• Known history of severe allergic reaction (including drugs, food, insect bites, environmental allergens);
• Known history of seizures (except febrile seizures prior to age 5), anorexia nervosa, bulimia or current diagnosis or family history of Tourette's disorder;
• Subject who are severely underweight or overweight.
• Clinical value outside of the acceptable ranges, unless deemed NCS significant per the Investigator;
• Positive history for hepatitis B, hepatitis C and Human Immunodeficiency Virus (HIV);
• Positive screening for illicit drug use, and/or current health conditions or use of medications that might confound the results of the study or increase risk to the subject;
• Use of prescription medications (except ADHD medications) within 7 days and over-the counter medications (except birth control) within the 3 days preceding study enrollment, unless deemed acceptable by the Investigator and Clinical and/or Medical Monitor;
• Blood draws of 50 ml to 249 ml within the 30 days, 250 ml to 449 ml within the 45 days and ≥ 450 ml within the 60 days preceding study enrollment;
• Participation in clinical trial with an investigational drug within the 30 days preceding study enrollment;
• Intolerance to venipuncture; and
• Current suicidal ideation or history of suicidality determined as a significant finding on the Columbia-Suicide Severity Rating Scale (C-SSRS) by the investigator (Baseline C-SSRS for adolescents; Pediatric Baseline C-SSRS for children).

Baseline to 48 hours after the HLD200 dose