TB-500 — pharmacology
Molecular targets, mechanism of action, pharmacokinetics and interactions as characterised in humans.
§2Pharmacology
§2.1Molecular targets
Table 2. Molecular targets recorded for TB-500, with the character of the interaction and the potency where the Institute holds it.
| Target | Interaction | Note |
|---|---|---|
| Actin (intracellular) | Binding motif | The parent protein sequesters G-actin; whether an extracellular heptapeptide reaches intracellular actin at meaningful concentration has not been demonstrated |
| Mechanism not established | No cell-surface receptor identified | No receptor for thymosin beta-4 or its fragments has been definitively identified |
§2.2Mechanism of action
Thymosin beta-4 is an abundant intracellular actin-sequestering protein with reported extracellular activity in angiogenesis, cell migration and wound repair. TB-500 comprises the actin-binding motif and is supplied on the premise that this fragment reproduces the parent protein's regenerative activity. The Institute notes a substantive mechanistic objection: the parent's principal characterised function is intracellular, and no transport mechanism has been described by which a small extracellular peptide would reach that compartment.[1,2]
§2.3Pharmacokinetics
No human pharmacokinetic characterisation of TB-500 has been identified. In the absence of a half-life, a volume of distribution and a clearance estimate, no dosing interval used in practice can be related to any exposure that produced an effect in any study, and the Institute records this as a first-order gap rather than a detail.
§2.4Interactions
- Not characterised
References cited on this page
References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.
- Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opinion on Biological Therapy 2012;12(1):37–51. doi:10.1517/14712598.2012.634793 · PMID 22074294
- Thevis M, Thomas A, Schänzer W. Detecting peptidic drugs, drug candidates and analogs in sports doping: current status and future directions. Expert Review of Proteomics 2019;11(6):663–673. doi:10.1586/14789450.2014.965158
Identifiers are reproduced only where the Institute holds them. Where a digital object identifier or PubMed identifier is not shown, the Institute has recorded the journal and year and has not constructed an identifier.