Effect of protein concentration on the binding of drugs to human serum albumin—I. Sulfadiazine, salicylate and phenylbutazone

Boobis, Susan; Chignell, Colin F.

doi:10.1016/0006-2952(79)90354-x

Cited by 43 publications

(19 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Preparation of Stock [ 14 C]Bilirubin-Radiolabeled bilirubin conjugates were purified from bile after intravenous infusion of ␦- [5][6][7][8][9][10][11][12][13][14] C]aminolevulinic acid (PerkinElmer Life Sciences, Boston, MA) to bile-fistula rats using a protocol approved by the Animal Committee of Northwestern University Medical School and the Chicago VA Lakeside Medical Center. Purified 14 C-unconjugated bilirubin was then obtained by a modification of the method of Ostrow et al (21).…”

Section: Methodsmentioning

confidence: 99%

“…The binding affinity of albumin has been reported to vary with albumin concentration for numerous other metabolites and drugs, including cortisol (8,11), sulfobromophthalein (12), thiopental (13), phenytoin (14), tryptophan (14,15), sulfadiazine (9), salicylate (9), phenylbutazone (9), and a benzoic acid derivative (16). The mechanism of this effect is unknown, but may reflect formation of reversible aggregates of albumin at higher concentrations.…”

Section: Table I Estimates Of Impurity Levels and Formation Rates Usimentioning

confidence: 99%

“…This assumption has never been adequately tested and has recently been questioned (5,6). Moreover, many properties of albumin are known to depend on its concentration (7)(8)(9)(10). In particular, the binding affinity of albumin for a variety of metabolites and drugs is reduced at higher albumin concentra-tion (8,9,(11)(12)(13)(14)(15)(16).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Affinity of Human Serum Albumin for Bilirubin Varies with Albumin Concentration and Buffer Composition

Weisiger¹,

Ostrow²,

Koehler³

et al. 2001

Journal of Biological Chemistry

106

View full text Add to dashboard Cite

Albumin binding is a crucial determinant of bilirubin clearance in health and bilirubin toxicity in certain disease states. However, prior attempts to measure the affinity of albumin for bilirubin have yielded highly variable results, reflecting both differing conditions and the confounding influence of impurities. We therefore have devised a method based on serial ultrafiltration that successively removes impurities in [ 14 C]bilirubin until a stable binding affinity is achieved, and then we used it to assess the effect of albumin concentration and buffer composition on binding. The apparent binding affinity of human serum albumin for [ 14 C]bilirubin was strongly dependent on assay conditions, falling from (5.09 ؎ 0.24) ؋ 10 7 liters/mol at lower albumin concentrations (15 M) to (0.54 ؎ 0.05) ؋ 10 7 liters/mol at higher albumin concentrations (300 M). To determine whether radioactive impurities were responsible for this change, we estimated impurities in the stock bilirubin using a novel modeling approach and found them to be 0.11-0.13%. Formation of new impurities during the study and their affinity for albumin were also estimated. After correction for impurities, the binding affinity remained heavily dependent on the albumin concentration (range (5.37 ؎ 0.26) ؋ 10 7 liters/mol to (0.65 ؎ 0.03) ؋ 10 7 liters/ mol). Affinities decreased by about half in the presence of chloride (50 mM). Thus, the affinity of human albumin for bilirubin is not constant, but varies with both albumin concentration and buffer composition. Binding may be considerably less avid at physiological albumin concentrations than previously believed.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Table I Estimates Of Impurity Levels and Formation Rates Usimentioning

confidence: 99%

See 1 more Smart Citation

Affinity of Human Serum Albumin for Bilirubin Varies with Albumin Concentration and Buffer Composition

Weisiger¹,

Ostrow²,

Koehler³

et al. 2001

Journal of Biological Chemistry

106

View full text Add to dashboard Cite

show abstract

“…Increase in K for bilirubin/albumin binding with sample dilution has been demonstrated by other binding methods [15,18], and this phenomenon has also been reported with other ligands thought to bind at the bilirubin site [24]. K is the ratio of the rate at which B f and free albumin combine to form the bilirubin-albumin complex to the rate at which bilirubin dissociates from its complex with albumin (rate 1 in steady state scheme in Methods) [23].…”

Section: Discussionmentioning

confidence: 62%

“…Since both instruments obtain B f from integrated rate equations that require measuring the change in TBC (change in absorbance at 460 nm corrected for haemoglobin) over time [14,22], it seems unlikely that any differences in B f with sample dilution would be solely due to intrinsic differences in the instruments. In addition, a decrease in B f with sample dilution was originally documented using a single instrument [16], and the phenomenon, which is not unique to B f [24], has been confirmed by ultrafiltration studies [18].…”

Section: Methodsmentioning

confidence: 92%

Effects of sample dilution, peroxidase concentration, and chloride ion on the measurement of unbound bilirubin in premature newborns

Ahlfors

Vreman

Wong

et al. 2007

Clinical Biochemistry

View full text Add to dashboard Cite

Objectives-To assess the effects of sample dilution, peroxidase concentration, and chloride ion (Cl -) on plasma unbound bilirubin (B f ) measurements made using a commercial peroxidase methodology (UB Analyzer) in a study population of ill, premature newborns.Design and Methods-B f was measured with a UB Analyzer in 74 samples at the standard 42-fold sample dilution and compared with B f measured at a 2-fold sample dilution using a FloPro Analyzer. B f was measured at two peroxidase concentrations to determine whether the peroxidase steady state B f (B fss ) measurements were significantly less than the equilibrium B f (B feq ), in which case it was necessary to calculate B feq from the two B fss measurements. B f was also measured before and after adding 100 mmol/L Cl -to the UB Analyzer assay buffer. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conclusions-B fss measured by the UB Analyzer at the standard 42-fold sample dilution using assay buffer without Cl -and a single peroxidase concentration is significantly less than the B feq in undiluted plasma. Accurate B f measurements can be made only in minimally diluted serum or plasma. Results-B NIH Public Access

show abstract

Stereoselective binding of etodolac to human serum albumin

et al. 1992

View full text Add to dashboard Cite

The protein binding of etodolac enantiomers was studied in vitro by equilibrium dialysis in human serum albumin (HSA) of various concentrations varying from 1 to 40 g/liter, by addition of each enantiomer at increasing concentrations. In the 1 g/liter solution, at the lowest drug levels, the (R)-form is more bound than its antipode, the contrary being observed at the highest drug levels. For higher albumin concentrations, S was bound in a larger extent than R. Using the displacement of specific markers of HSA sites I and II, studied by spectrofluorimetry, it was suggested that R and S are both bound to site I, while only S is strongly bound to site II.

show abstract

Effect of protein concentration on the binding of drugs to human serum albumin—I. Sulfadiazine, salicylate and phenylbutazone

Cited by 43 publications

References 18 publications

Affinity of Human Serum Albumin for Bilirubin Varies with Albumin Concentration and Buffer Composition

Affinity of Human Serum Albumin for Bilirubin Varies with Albumin Concentration and Buffer Composition

Effects of sample dilution, peroxidase concentration, and chloride ion on the measurement of unbound bilirubin in premature newborns

Stereoselective binding of etodolac to human serum albumin

Contact Info

Product

Resources

About