Covalently bound conjugates of albumin and heparin: Synthesis, fractionation and characterization

Hennink, Wim E.; Feijén, Jan; Ebert, C. D.; Kim, Sung Wan

doi:10.1016/0049-3848(83)90120-2

Cited by 60 publications

(18 citation statements)

References 13 publications

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“…The protocol used to synthesize the soluble albumin-heparin conjugate was based on the method of Hennink et al (8). The procedure was slightly modified to inhibit denaturation of the serum albumin.…”

Section: Synthesis Of Albumin-heparin Conjugatementioning

confidence: 99%

Preparation and characterization of microspheres of albumin-heparin conjugates

Kwon¹,

Bae²,

Kim³

et al. 1991

Journal of Colloid and Interface Science

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Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form albuminheparin microspheres. The composition of the conjugate was determined by amino acid analysis. The swelling properties of albumin-heparin microspheres were investigated as a function of pH and ionic strength and compared with albumin microspheres. Albumin-heparin and albumin microspheres exhibited stimuli-sensitive swelling. Both microsphere systems exhibited low swelling at low pH and high swelling at higher pH caused by ionization of amino acids of serum albumin. The swelling of albumin-hepafin microspheres was more sensitive toward ionic strength than that of albumin microspheres. This was due to the greater negative charge of the albumin-heparin microspheres. Surfaces of albumin-heparin and albumin microspheres were characterized by ESCA, contact angle measurements, electrophoresis, and scanning electron microscopy. Surface analysis indicated the presence of heparin at the albumin-heparin microsphere/water interface.

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Section: Synthesis Of Albumin-heparin Conjugatementioning

confidence: 99%

Preparation and characterization of microspheres of albumin-heparin conjugates

Kwon¹,

Bae²,

Kim³

et al. 1991

Journal of Colloid and Interface Science

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“…Corresponding fractions were combined. The heparin concentration of the different fractions was determined with the metachromic assay as described by Jaques et al (9), modified as described previously (10). Subsequent fractions were pooled till a dry weight of 0.5 g was expected.…”

Section: Fractionation Of Heparinmentioning

confidence: 99%

“…The anticoagulant activity of the heparin fractions obtained with Biogel P 200 was determined using the thrombin time assay (10) and the activated partial thromboplastin time (APTT) assay (10). The chromogenic anti-factor Xa assay was performed as described by Teien et al (24).…”

Section: Anticoagulant Activity Of Heparin Fractionsmentioning

confidence: 99%

“…The pooled fractions were dialyzed against water and lyophilized. Antithrombin III was immobilized onto CNBr-activated Sepharose as described previously (10). A sample of heparin (4 ml containing 1 mg heparin per ml Tris-buffer) was passed over the AT III-Sepharose column and eluted with 2 column volumes of buffer yielding low affinity heparin fractions.…”

Section: Fractionation Of Heparinmentioning

confidence: 99%

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Complement inhibitory and anticoagulant activities of fractionated heparins

Hennink

Klerx

Dijk

et al. 1984

Thrombosis Research

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Almost monodisperse heparin fractions (Rw/%r < 1.1) were obtained by gel filtration of a commercial heparin. These fractions were assayed for anticoagulant activity (thrombin times and APTT), chromogenic anti-factor Xa activity, inhibitory activity for the human classical complement pathway, carboxyl group content and total sulfate content. Linear relationships were observed between the molecular weight of the heparin fractions and the anticoagulant activities as determined by thrombin time-and APTTassay and the classical complement pathway inhibitory activity.On the other hand a hyperbolic-like relationship was observed between the molecular weight of the heparin fractions and the chromogenic anti-factor Xa activity. The heparin fractions did not show significant differences with respect to the carboxyl group and total sulfate content. Low-and high affinity heparin fractions were obtained by affinity chromatography using immobilized AT III. High-and low-affinity fractions greatly differed not only with respect to their APTT activity, but also where their complement-inhibitory activities were concerned. The latter in contrast to literature data available. These differences could not be explained by the observed differences in molecular weight of high and low affinity heparin respectively.

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“…These microspheres have been synthesized by techniques similar to the preparation of albumin microspheres either starting with an aqueous mixture of albumin and heparin followed by stabilization with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and glutaraldehyde, respectively, or by use of preformed soluble albumin-heparin conjugates [17], which are stabilized with glutaraldehyde. In this way hydrophilic, biodegradable microspheres composed of endogenous materials are obtained.…”

Section: Introductionmentioning

confidence: 99%