Bioavailability
Notice
ALL ARTICLES AND PRODUCT INFORMATION PROVIDED ON THIS WEBSITE ARE FOR INFORMATIONAL AND EDUCATIONAL PURPOSES ONLY. The products offered on this website are furnished for in-vitro studies only. In-vitro studies (Latin: in glass) are performed outside of the body. These products are not medicines or drugs and have not been approved by the FDA to prevent, treat or cure any medical condition, ailment or disease. Bodily introduction of any kind into humans or animals is strictly forbidden by law.
What is Bioavailability?
Bioavailability is a pharmacokinetic term that describes the fraction of an administered substance that reaches systemic circulation in an unchanged, active form and is therefore available to produce a biological effect. In research contexts, bioavailability is a critical parameter for understanding how efficiently a peptide or other compound is absorbed and utilized by the biological system under study. A substance with 100% bioavailability (such as one administered directly into the bloodstream) is fully available, while substances administered by other routes may have significantly lower bioavailability due to processes like enzymatic degradation, poor absorption, or first-pass metabolism.
Factors Affecting Peptide Bioavailability
Peptides present unique bioavailability challenges compared to small-molecule compounds. Their relatively large molecular size, susceptibility to enzymatic degradation by proteases, and often limited ability to cross biological membranes can all reduce bioavailability. Key factors that influence a peptide's bioavailability include:
- Route of Administration: Different administration routes (e.g., subcutaneous, intraperitoneal, oral) result in vastly different bioavailability profiles for peptides.
- Molecular Weight and Size: Larger peptides generally have more difficulty crossing biological membranes.
- Enzymatic Stability: Peptides are susceptible to degradation by proteolytic enzymes in the gastrointestinal tract, bloodstream, and tissues.
- Charge and Hydrophobicity: The physicochemical properties of a peptide's amino acid sequence influence membrane permeability and absorption rates.
Improving Peptide Bioavailability in Research
Researchers employ several strategies to enhance peptide bioavailability in experimental settings. These include chemical modifications such as cyclization, N-methylation, or substitution with non-natural amino acids to improve protease resistance. Formulation approaches like encapsulation in nanoparticles or liposomes can also protect peptides from degradation and facilitate cellular uptake. Understanding and optimizing bioavailability is an active and important area of peptide research that directly impacts the translation of in vitro findings to meaningful in vivo observations.