ULTRAVIOLET(UV) SPECTROSCOPY OF HEPARIN

ABSTRACT

Ultraviolet (UV) spectroscopy simply involve the use of ultraviolet (UV) light to determine the absorbance of a sample. It obeys Beer-Lambert’s law which states that the absorbance of light by a sample is directly proportional to the concentration and path length of the sample. Ultraviolet (UV) spectroscopy is used widely for identification and characterization of a compound. The use of ultraviolet (UV) spectra for the identification and characterization of heparin is the focus of this work. Heparin is a well-known anticoagulant drug and is extensively used in medical practice. The features of the UV- spectra of glycosaminoglycans (GAGs) arise predominantly from electronic transition in the carboxylate group of the uronate residues and the N-acetyl chromophores in the glucosamine residue. The carboxylate group being responsible for the majority of the spectra features. In general, any functional group that engages in hydrogen bonding, such as, alcohol and carboxylic acids, will have broad peaks. More generally, functional groups that have strong intermolecular interaction have broad peaks, and functional group that have weak intermolecular interaction will have narrow peaks (de Micalizzi et al., 1998). While both reactive and pharmaceutical grade heparin show maximum absorbance at 190-210 nm, the pharmaceutical grade heparin shows additional peaks at 255-260 nm, due to the benzyl alcohol used as preservative in the preparation. The unwholesome contaminants display peaks of different pattern