Study Evaluating the Effect of TC-6499 on Gastric Emptying Time in Diabetic Subjects With Gastroparesis

Inclusion Criteria: * A diagnosis of gastroparesis or symptoms consistent with gastroparesis for at least 6 months (and Gastroparesis Cardinal Symptoms Index total score \>22) * Gastroparesis confirmed using the GEBT * Type 1 or Type 2 diabetes with a Hemoglobin A1c ≤ 10% * Fasting blood glucose (finger stick) ≤ 275 mg/dL prior to each GEBT * Body Mass Index (BMI) ≤ 40 * Willingness to remain in clinical research facility for the protocol-required days of treatment and study procedures * Willingness to use a double barrier method of birth control (except post-menopausal females) * Able to understand study procedures and provide written informed consent Exclusion Criteria: * History of abdominal surgery including gastric banding procedure * Chronic parenteral feeding or feeding through a gastrostomy or jejunostomy tube * Persistent daily vomiting * A history of eating disorder * Recent history of poor control of diabetes * Acute severe gastroenteritis * Have implanted or use any type of gastric electric stimulator * Use of opiates, anticholinergic medications, GLP-1 mimetics or amylin analogs * Use of medications potentially influencing upper gastrointestinal motility or appetite * Allergies or intolerance to egg, wheat, milk, or algae * Pregnant or lactating females * Presence of a clinically significant medical condition at any time during the study * Presence of clinically significant abnormalities in laboratory findings, physical exam findings or vital signs * Participated in an investigational drug study within 30 days of screening