Pharmacokinetic Study of LY03003 in Patients With Parkinson's Disease

Inclusion Criteria: * Capable of giving informed consent and complying with trial procedures including the ability to stay at/return to the CRU for visits at the predetermined times on the prescribed schedule. * Has idiopathic Parkinson's Disease (i.e., without any other known or suspected cause of Parkinsonism) defined by the cardinal signs, bradykinesia, plus the presence of ≥1 of the following: resting tremor, rigidity, or impairment of postural reflexes. * Male or female patient ≥18 years old with BMI of 18.5 to 32 kg/m2, inclusive, and body weight ≥50 kg at Screening. * MMSE score ≥25 at Screening. * UPDRS motor (Part III) score ≥ 10 but ≤ 42 at Screening. * All female patients (childbearing potential and non-childbearing potential) must have a negative serum pregnancy test result at Screening. In addition, female patients must meet 1 of the following 3 conditions: (i) postmenopausal for at least 12 months without an alternative medical cause, (ii) surgically sterile (hysterectomy, bilateral oophorectomy, bilateral salpingectomy, or bilateral tubal occlusion) based on patient report, or (iii) if of childbearing potential, practicing or agree to practice a highly effective method of contraception. Exclusion Criteria: * Atypical Parkinson's syndrome(s) due to drugs (e.g., metoclopramide, flunarizine), metabolic neurogenetic disorders (e.g., Wilson's Disease), encephalitis, cerebrovascular disease, or degenerative disease (e.g., progressive Supranuclear Palsy). * History of pallidotomy, thalamotomy, deep brain stimulation, or fetal tissue transplant. * Dementia, active psychosis or hallucinations, or clinically significant major depression requiring psychiatric interventions. * Lifetime history of suicide attempt (including an active attempt, interrupted attempt, or aborted attempt) or suicidal ideation in the past 6 months as indicated by a positive response ("Yes") to either Question 4 or Question 5 of the C-SSRS. * History of symptomatic orthostatic hypotension with a decrease of ≥20 mmHg in SBP or decrease of ≥10 mmHg in DBP when changing from supine to standing position after having been in the supine position for at least 5 minutes or SBP less than 105 mmHg in a supine position at the Screening Visit. * Therapy with a dopamine (DA) agonist either concurrently or within 21 days prior to study drug dosing. * Therapy with 1 or more of the following drugs either concurrently or within 21 days prior to study drug dosing: monoamine oxidase inhibitors, DA releasing agents, DA modulating agents, DA antagonists, DA depleting antihypertensives, tricyclic antidepressants, neuroleptics, or other medications that may interact with DA function. * Current diagnosis of epilepsy, history of seizures as an adult, lifetime history of stroke, or transient ischemic attack (TIA) within 1 year prior to the Screening Visit. * Female patient who is pregnant or breastfeeding or of childbearing potential without adequate contraception * History of prescription drug abuse or illicit drug use, alcohol abuse, or tobacco use within 6 months prior to the Screening Visit or positive finding in drugs of abuse test, nicotine test, or alcohol test. * Any other clinically relevant hepatic, renal, hematologic, and/or cardiac dysfunction, or other medical condition, or clinically significant laboratory abnormality that would interfere with the patient's safety or trial outcome in the judgment of the Investigator.