heparitin-sulfate and tetrabutylammonium

In this study, by using tetrabutylammonium bisulfate as ion-pairing reagent, we were able to separate all the main heparin/heparan sulfate disaccharides generated by the action of heparinases along with the main Hep tetrasaccharide possessing a 3-O-sulfate group on the sulfoglucosamine unit and resistant to enzymatic action. Moreover, this novel HPLC method was able to separate and quantify uncommon disaccharides/oligosaccharides present in low molecular weight-heparins produced by chemical treatment with nitrous acid, dalteparin, or benzylation followed by alkaline hydrolysis, enoxaparin. Additionally, this procedure yields a sensitivity ∼4-times higher compared to conventional strong-anion exchange-HPLC separation. This was obtained by a common UV detector at 232 nm avoiding the use of complex procedures capable of increasing sensitivity by post-column derivatization. Finally, it is worth mentioning that disaccharide/oligosaccharide composition by HPLC and UV detection is a common analytical approach in quality control laboratories to evaluate heparins and low molecular weight-heparins structure and quality during their extraction and production. This simple HPLC approach offers high resolution and sensitivity for the rapid differentiation of pharmaceutical native heparins and derivatives and for the compositional analysis of small amounts of samples derived from biological sources at a glycosaminoglycans level of a few hundred nanogram.

Topics: Animals; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Heparin; Heparitin Sulfate; Oligosaccharides; Quaternary Ammonium Compounds; Sensitivity and Specificity; Swine

In this report we describe a convenient and sensitive HPLC method for separating and determining the non- and variously sulphated delta-disaccharides derived from heparan sulphate, heparin and Fragmin, using heparin- and heparan sulphate lyases. This method is superior to others since it can separate and determine twelve different non-, mono-, di- and trisulphated delta-disaccharides containing either N-sulphated, N-acetylated or unsubstituted glucosamine in a single HPLC run. The various types of delta-disaccharides are separated by an ion-pair reversed-phase chromatographic procedure on a Supelcosil LC-18 column, using a binary acetonitrile gradient system with tetrabutylammonium as the ion-pairing reagent. The eluted peaks were recorded by dual wavelength at 232 and 226 nm and a linear detector response was obtained over the entire interval tested, i.e., to 50 micrograms of delta-disaccharides. As little as 0.8-5 ng of delta-disaccharides can be reliably detected and accurately determined. Following separate digestion with the heparin- and heparan sulphate lyases (heparin lyases I, II and III), the characteristic heparin delta-disaccharides in the heparan sulphate chain, as well as the heparan sulphate delta-disaccharides in the heparin polymer, can be identified. Using combined digestions with these three lyases, the glycosaminoglycan chains are degraded almost completely (> 90%) to delta-disaccharides, which are then determined by direct injections into the HPLC system and thus an almost complete spectrum of disaccharide composition can be obtained. By this method, it is possible to analyse and confirm that the heparan sulphate chain is defined as a glycosaminoglycan dominated by GlcNAc(+/- 6S)-GlcA disaccharides and by some copolymeric disaccharides, such as GlcNS-IdoA2S and GlcNS6S-IdoA2S, otherwise most common in heparin. Fragmin, which is a controlled cepolymerized heparin fragment of M(r) 5000, is made up mainly of trisulphated disaccharides of the GlcNS6S-IdoA2S type (88.8%). Using separate digestions with the specific heparin lyases, one can also distinguish between heparin and heparan sulphate.

Topics: Acetonitriles; Chromatography, High Pressure Liquid; Dalteparin; Disaccharides; Glycosaminoglycans; Heparin; Heparitin Sulfate; Indicators and Reagents; Quaternary Ammonium Compounds; Reproducibility of Results; Sensitivity and Specificity