Towards a novel drug therapy for treatment-resistant depression, adjunct 5-HTP slow-release: determining the human colonic absorption of 5-HTP


Project Outline

Depression is the leading cause of disability worldwide, and is a major contributor to the global burden of disease. Selective serotonin-reuptake inhibitors (SSRIs) are the first line pharmacotherapy in depression but only one third of patients will recover with this treatment. Improved forms of antidepressant treatment are urgently needed. One promising way is to elevate serotonin levels to beyond what SSRIs are capable of, by using adjunctive 5-hydroxytryptophan (5-HTP). 5-HTP is an amino acid that is essential for serotonin biosynthesis in the brain. However 5-HTP makes a poor oral drug because it is rapidly metabolized and has a very short half-life. We aim to overcome this by developing a 5-HTP drug that will provide a steady release of 5-HTP over time; a 5-HTP sustained release (SR) drug.

Project Deliverables

The SR formulations we intend to use are broadly classified as either colon-dependent or colon-independent. Colon absorption of 5-HTP will be compared against upper gastrointestinal absorption to determine which SR formulation would best suit 5-HTP SR drug development.


Principal Investigator: Dr Johnson FAM

Institution: National University Hospital Singapore

NHIC Ref: NHIC-I2D-1503044