Plasma and serum protein

Plasma and serum protein refers to the heterogeneous collection of proteins found in the liquid portion of blood, including albumin, globulins, and fibrinogen (StatPearls, 2023). These proteins perform essential physiological roles such as maintaining colloid osmotic pressure, buffering blood pH, and transporting lipids, hormones, and vitamins throughout the body (Wikipedia, 2024). While the category itself is not a single therapeutic target, it is of paramount importance in pharmacology because the majority of drugs bind to these proteins, particularly albumin and alpha-1-acid glycoprotein (PubMed, 2021). This binding determines the "free fraction" of a drug, which is the pharmacologically active portion capable of diffusing to target tissues (NIH, 2023). Pathological conditions like cirrhosis or nephrotic syndrome can significantly alter protein levels, leading to unpredictable drug responses or increased risk of toxicity due to displacement or reduced binding capacity (NCBI, 2023). Furthermore, specific proteins within this group, such as clotting factors or complement components, serve as specific targets for various hematological and immunological therapies (PubMed, 2020). Understanding these interactions is vital for predicting drug-drug interactions, especially for drugs with a narrow therapeutic index (NCBI, 2023).

Other names

Blood proteinsSerum proteinsPlasma proteomeCirculating proteins

Drugs interact with these proteins primarily through reversible, non-specific binding, which regulates the systemic distribution and the pharmacologically active free fraction of the drug in circulation.