Removal of stabilizers from human serum albumin by adsorbents and dialysis used in blood purification

Abstract

IntroductionHuman serum albumin (HSA) is a monomeric multi-domain protein that possesses an extraordinary binding capacity. It plays an important role in storing and transporting endogenous substances, metabolites, and drugs throughout the human circulatory system. Clinically, HSA is used to treat a variety of diseases such as hypovolemia, shock, burns, hemorrhage, and trauma in critically ill patients. Pharmaceutical-grade HSA contains the stabilizers sodium caprylate and N-acetyltryptophanate to protect the protein from oxidative stress and to stabilize it for heat treatment which is applied for virus inactivation.Material and methodsThe aim of this study was to determine if the two stabilizers can be depleted by adsorbent techniques. Several, adsorbents, some of them are in clinical use, were tested in batch and in a dynamic setup for their ability to remove the stabilizers. Furthermore, the removal of the stabilizers was tested using a pediatric high flux dialyzer.ResultsThe outcome of this study shows that activated charcoal based adsorbents are more effective in removal of N-acetylthryptophanate, whereas polystyrene based adsorbents are better for the removal of caprylate from HSA solutions. An adsorbent cartridge which contains a mix of activated charcoal and polystyrene based material could be used to remove both stabilizers effectively. After 4 hours treatment with a high flux dialyzer, N-acetyltryptophanate was totally removed whereas 20% of caprylate remained in the HSA solution.

Absence of the CXCR4 Antagonist EPI-X4 from Pharmaceutical Human Serum Albumin Preparations

“…Albumin is the most abundant protein in plasma (3.5-4.5 g/dL) and represents more than half the total plasma protein content [1] [2][3] [4]. It is produced by the liver at fairly constant quantities of 9-12 g/dL [1] [4] [3], and has a plasma half-life of approximately 19 days [4], with modest up-and downregulation by loss of colloid osmotic pressure or certain hormones and inflammatory cytokines, respectively [1] [2][5] [6] [7] [8]. Albumin is considered the main modulator of fluid distribution and main generator of oncotic pressure [1] [2][4] since acquired hypoalbuminemia is associated with arterial hypotension all the way to circulatory shock, intravascular volume depletion and pitting edema.…”

“…Upon X-ray crystallography, albumin appears heart-shaped with domains I, II and III corresponding to the left ear, tip and right ear of the "heart". EPI-X4 is cleaved from subunit 1 of domain III [3][4] [13].…”

“…The latter come with the advantage that other plasma proteins of interest can be recovered from the run-through. After near-homogenous purification, medicinal HSA is subsequently sterilized by heat treatment (60 °C for 10-11 hours) which necessitates addition of certain stabilizers, critically including caprylate and N-acetyl-tryptophanate, both at a concentration of 4 mM [20], to reduce oxidative stress and limit denaturation or aggregation [3]. Medicinal HSA is approved for the substitution treatment of albumin loss, for example systemic capillary leakage or nephrotic syndromes, or general protein loss such as in burn injuries, as well as failure to generate sufficient albumin such as in liver failure [1][3] [4].…”

Absence of the CXCR4 antagonist EPI-X4 from pharmaceutical human serum albumin preparations

“…Upon X-ray crystallography, albumin appears heart-shaped with domains I, II and III corresponding to the left ear, tip and right ear of the “heart”. EPI-X4 is cleaved from subunit 1 of domain III [ 3 , 4 , 13 ].…”

Aggregate Removal Nanofiltration of Human Serum Albumin Solution Using Nanocellulose-Based Filter Paper

“…[21]. However, the presence of high quantities of HSA stabilizers (e.g., typical stabilizer: Albumin molar ratio > 5:1) negatively affects the binding and transport properties of HSA, especially with respect to lipophilic molecules [22,23]. Further, pasteurized HSA does not have the redox properties of native HSA and contains higher quantities of cysteinylated, i.e., Cys34-bound, albumin, especially S-nitrosoalbumin [24].…”