Ligand Half-Life
Depending on the model, ligands may either be soluble or membrane bound. Ligand half-life, \(t_{1/2,L}\) for soluble, \(t_{1/2,mL}\) for membrane bound. Soluble ligands can be the target of the biotherapeutic or the competitive binding partner of the receptor target. Membrane ligands are the competitive binding partner of the receptor target.
This documentation focuses on soluble ligands. For membrane-bound ligand half-life, see the receptor half-life documentation, as \(t_{1/2,mL}\) is determined in the same fashion as \(t_{1/2,R}\).
Ligand half-life is the half-life of the elimination of the ligand.
Ligand Half-Life in Assess
Soluble ligand half-life is best identified from measured clearance (plasma pharmacokinetics) of exogenously administered ligand. Data from preclinical animal models can be converted to human-specific values through allometric scaling.
For soluble ligands that are rapidly degraded by endogenous enzyme (e.g. glucagon-like peptide-1 (GLP-1)), ex vivo serum stability measurements may help inform the half-life.
In the absence of data, a reasonable range may be obtained using comparators of a similar molecular weight. (Li et al. 2017; Kuna et al. 2018)
References
- Li Z, Krippendorff BF, Shah DK. Influence of Molecular size on the clearance of antibody fragments. Pharm Res. 2017;34(10):2131-2141. doi:10.1007/s11095-017-2219-y
- Kuna, M., Mahdi, F., Chade, A.R. et al. Molecular Size Modulates Pharmacokinetics, Biodistribution, and Renal Deposition of the Drug Delivery Biopolymer Elastin-like Polypeptide. Sci Rep 8, 7923 (2018). https://doi.org/10.1038/s41598-018-24897-9