Plasma proteins and tissue components

Plasma proteins and tissue components refer to a broad category of biological entities that interact with drugs non-specifically, primarily influencing their distribution and pharmacokinetics rather than serving as intended therapeutic targets. This group includes major blood proteins such as human serum albumin, which binds acidic drugs, and alpha-1-acid glycoprotein, which binds basic drugs (StatPearls, 2023). Tissue components encompass structural elements like hydroxyapatite in bone or lipids in adipose tissue, which can sequester specific drug classes, acting as long-term reservoirs (PubMed, 2021). While these interactions are essential for determining a drug's half-life and volume of distribution, they are also the source of significant drug-drug interactions through displacement from binding sites (NIH, 2022). In clinical settings, conditions that alter the concentration of these components, such as hypoalbuminemia in liver disease or protein loss in renal failure, can lead to increased free drug fractions and subsequent toxicity (PubChem, 2024). Consequently, monitoring these components is vital for the safe administration of drugs with high protein-binding affinity and narrow therapeutic windows (Wikipedia, 2023).

Other names

Plasma protein binding sitesTissue binding sitesNon-specific binding sitesSerum proteinsExtracellular matrix components

Non-specific reversible binding to plasma proteins and sequestration in tissue matrices, which modulates the volume of distribution and the concentration of free, pharmacologically active drug (StatPearls, 2023; NIH, 2022).