Glycine
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Glycine: From Allergic Rhinitis and Related Upper Airway Conditions to Nasal Cavity Disease
One-Sentence Summary
Glycine is an amino acid that is widely marketed in Singapore, mainly in parenteral nutrition products. In the knowledge graph used for this report, its original indications are allergic rhinitis, vasomotor rhinitis, pharyngitis, the common cold, rhinitis and nasopharyngitis. The TxGNN model predicts it may be effective for nasal cavity disease, but only 1 clinical trial (an unrelated imaging study) and 2 publications (basic research) are linked, so there is effectively no supporting evidence beyond the model prediction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Allergic rhinitis, vasomotor rhinitis, pharyngitis, common cold, rhinitis, nasopharyngitis (from the knowledge graph; Singapore licence records contain no indication text) |
| Predicted New Indication | Nasal cavity disease |
| TxGNN Prediction Score | 99.85% |
| Evidence Level | L5 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 19 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, glycine is an amino acid used as a nutritional component and as an inhibitory neurotransmitter. Its listed original indications are all upper airway and nasal conditions, and nasal cavity disease is a closely related category.
The very high score (99.85%) most likely reflects overlap with those original indications, since rhinitis is itself a nasal cavity disease. It is not evidence of a new mechanism. No mechanistic rationale can be confirmed, and the linked trial and papers do not show that glycine is effective in nasal disease.
Other predictions for this drug are also computational only. The closest is acute laryngopharyngitis (99.84%), which is similar to the original indications. Dyspepsia (96.4%) has only indirect animal-study evidence.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT01806675 | Phase 1/2 | Completed | 25 | PET imaging of angiogenesis (αvβ3 integrin) in glioblastoma, gynaecological cancer and renal cell carcinoma. It is a diagnostic study that does not test glycine as a therapy, and the link is likely incidental. |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 7771054 | 1995 | Basic research | Veterinary Pathology | Lectin histochemistry of normal and herpesvirus-infected bovine nasal mucosa. It does not test glycine. |
| 29607903 | 2018 | Basic research | Chemical & Pharmaceutical Bulletin | Oligoarginine-polymer conjugates as a nasal mucosal vaccine adjuvant in mice. It does not test glycine as a treatment. |
Singapore Market Information
Glycine has 19 valid single-ingredient registrations, with no cancelled ones. No approved indication text is recorded for these products. Most are parenteral nutrition or amino acid infusion products. Five representative authorizations:
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN12172P | Glyprin Dispersible Tablet | Tablet | Not recorded |
| SIN16337P | Aminoven Solution for Infusion 15% | Infusion, solution | Not recorded |
| SIN11682P | Aminoven Solution for Infusion 5% | Injection | Not recorded |
| SIN08352P | Aminoplasmal-15% Infusion | Injection | Not recorded |
| SIN09353P | Nutrineal PD4 with 1.1% Amino Acid Solution | Solution, sterile | Not recorded |
The registered dosage forms are an oral tablet, injectables, a sterile solution and emulsions. No nasal or topical formulation appears among them, so route compatibility with a nasal indication has not been established.
Safety Considerations
- Contraindications (from the knowledge graph, not label text): The graph links glycine to conditions including kidney disease (chronic kidney disease, end-stage renal failure), heart and cardiovascular disease, hypercalcaemia and hyperparathyroidism, nephrolithiasis, hyperphosphatemia, phenylketonuria and other disorders of phenylalanine metabolism, sarcoidosis, digitalis poisoning and ventricular fibrillation. These are database associations and should be checked against the package insert.
- Drug Interactions: No interaction records were found.
Please refer to the package insert for complete safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests on a model score that mostly reflects overlap with glycine's existing rhinitis-related indications. The one linked trial and two papers do not test glycine in nasal disease, and no mechanism has been established. This is evidence level L5.
To proceed, the following is needed:
- Package insert warnings and contraindications from the Singapore regulator (HSA), which are currently missing and block safety screening
- Mechanism of action data (for example from DrugBank) to assess biological plausibility
- Clarification of the approved indications for the registered products
- Direct preclinical or clinical studies of glycine in nasal cavity disease, plus a feasibility assessment of a nasal or topical route, since current formulations are oral and parenteral
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.