Understand the source comparison
TB-4 Metabolism Research: Model Comparison
In Vitro (cell culture) Limited proteolysis. Serum-free media lack POP and ACE, minimal Ac-SDKP generation Not applicable. Add exogenous fragments if testing fragment activity None. Uptake depends on transporter expression, not perfusion Low. Controlled variab
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This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- In Vitro (cell culture)
- Limited proteolysis. Serum-free media lack POP and ACE, minimal Ac-SDKP generation
- Not applicable. Add exogenous fragments if testing fragment activity
- None. Uptake depends on transporter expression, not perfusion
- Low. Controlled variables, reproducible
- Best for isolating intact TB-4 mechanisms; useless for fragment pharmacology unless fragments are added separately
- Ex Vivo (tissue explants)
- Tissue-resident protease activity. Variable by tissue type and preservation method
- 1-3 hours in metabolically active explants
- Reflects source tissue enzyme profile
- Moderate. Maintains tissue architecture but limited metabolic capacity
- Useful for tissue-specific metabolism mapping; short viability window limits long-term kinetics
- In Vivo (rodent models)
- Full systemic metabolism. POP, ACE, MMP activity; plasma protein binding; multi-organ distribution
- 2-4 hours post-injection
- Cardiac > skeletal muscle > dermis > hepatic
- High. Most physiologically relevant but significant inter-animal variability
- Gold standard for pharmacokinetic profiling and fragment bioactivity; expensive and requires validated LC-MS/MS methods
- Computational (PBPK modeling)
- Predicted based on enzyme kinetics, protein binding constants, tissue partition coefficients
- Model-dependent. Outputs only as reliable as input parameters
- Requires experimental validation for each tissue compartment
- Moderate to High. Depends on parameter availability
- Powerful for hypothesis generation and dose optimization; cannot replace experimental validation