The MADRS is a 10-item checklist of depressive symptoms. Each Item is rated on a scale of 0-6, with anchors at 2-point intervals; higher scores indicating more severity (i.e., ranging from 0 \[no sadness\] to 6 extremely despondent\]). The total MADRS score was calculated by summing the ratings of all items. The total MADRS score for this measure ranges from 0 (absence of symptoms) to 60 (maximum severity).

Change in Montgomery-Åsberg Depression Rating Scale (MADRS) total score from baseline to week 1, 2, 3, 4, and 5 in patients taking 1 or 2 PDC-1421 capsules. The MADRS is a 10-item checklist including 1) depression \[apparent\]; 2) depression \[reported\]; 3) loss of interest; 4) suicidal ideation; 5) tension; 6) reduced appetite; 7) insomnia; 8) difficulty in activities; 9) concentration; and 10) pessimism. The MADRS is administered by a trained interviewer. Each item is rated on a scale of 0-6, with anchors at 2-point intervals; higher scores indicating more severity (i.e., ranging from 0 \[no sadness\] to 6 \[extremely despondent\]). The total score is used to define treatment response (≥50% reduction from baseline) and partial response (20-49% reduction from baseline). Remission is defined as a score of \< 10. The following are used as an interpretation of scores: 0 to 6 - normal/symptom absent 7 to 19 - mild depression 20 to 34 - moderate depression \>34 - severe depression

Physical examination, including skin, head, neck, eyes, ears, nose, throat, heart, lungs, abdomen (liver and spleen), neurological examination, lymph node and extremities, is measured at each visit from screening to follow-up.

Electrocardiograph (ECG) is measured at each visit. At visit 2, subjects were measured at 1,2, 4, 8, 12 and 24 hours after drug administration.

Vital sign, including heart rate, blood pressure and body temperature, are measured at each visit and at 1,2,3,4,8,12 and 24 hours after drug administration.

Laboratory tests are composed of hematology and blood chemistry and measured at each visit. Hematology are composed of RBC, WBC, platelets, hematocrit, hemoglobin, prothrombin time (PT) and partial thromboplastin time (aPTT). Blood chemistry are composed of AST, ALT, LDH, total bilirubin, BUN, serum creatinine, free thyroxine (FT4), TSH, sodium, calcium, potassium, glucose, LDL, HDL, cholesterol and HbA1c.

C-SSRS is composed of suicidal ideation, intensity of ideation and suicidal behavior and measured at each visit.