A Relative Efficacy and Safety Study of OC Oral Solution for Sialorrhoea in Patients With Parkinson's Disease

Inclusion Criteria: * Diagnosis of Parkinson's Disease for at least 2 years * Patients with a score of ≥2 on the salivation section of UPDRS, item 6 * Patients Hoehn and Yahr stage must be ≤4 * under stable anti-Parkinson therapy throughout the study * Able and willing to comply with the study procedures * Able to provide and provision of a written informed consent Exclusion Criteria: * Female who is pregnant/lactating or planning to be pregnant * Must not have a form of drug-induced or atypical parkinsonism or parkinsonism with swallow problems due to other etiology * Have current uncontrolled hypertension, symptomatic postural hypotension, active Raynaud's disease or other peripheral vascular occlusive disease * Have a history or presence of hyperthyroidism, congestive heart failure, coronary heart disease, cardiac arrhythmias, tachycardia or severe bradycardia resulting from either sick sinus syndrome or AV block of 2nd or 3rd degree * Have a history of narrow angle glaucoma or shallow anterior chamber * Have a history or presence of gastrointestinal obstruction, including paralytic ileus and intestinal atony or gastrointestinal motility disorders, toxic megacolon or severe ulcerative colitis * Have a history or presence of bladder outflow obstruction or urinary retention * Patients with hepatic or renal impairment * Male with QTc \> 430 ms or female with QTc \> 450 ms ECG results at screening * Concomitant use of α2-agonist, anticholinergic medication or other medicati…