Albumin constitutes 60% of plasma proteins and exhibits exceptional structural stability due to its 17 disulfide bonds and conserved N-glycosylation. Beyond maintaining 80% of plasma oncotic pressure to prevent vascular fluid leakage, albumin binds and transports hydrophobic ligands-including fatty acids, steroids, thyroid hormones, calcium ions, and over 90% of circulating drugs-via its dynamic binding pockets. Its free Cys34 residue confers antioxidant properties by scavenging reactive oxygen species.

Hypoalbuminemia (<3.5 g/dL) arises from hepatic dysfunction (cirrhosis, hepatitis), renal protein loss (nephrotic syndrome), chronic inflammation, or malnutrition. Clinically, it manifests as edema, ascites, and impaired drug efficacy due to reduced ligand binding. Conversely, glycated albumin contributes to diabetic complications by promoting vascular endothelial dysfunction 3.

Therapeutically, human serum albumin (HSA) has been administered since 1941 for hypovolemia and burns, with modern 5% and 25% solutions managing ARDS and cardiopulmonary bypass. With a 19-day circulatory half-life, albumin stabilizes cell culture media.