Biomaterial Database

Structural changes in xanthan gum solutions during steam sterilization for sterile preparations. 2007

Aditya Bindal, and Ganesan Narsimhan, and Stanley L Hem, and Alok Kulshreshtha

Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA.

Steam sterilization of xanthan gum solutions at 121 degrees C caused a decrease in the helix conformation as well as the molecular weight distribution with a corresponding increase in the coil structure. The effect was directly related to the exposure time and inversely to the xanthan gum concentration, thus suggesting a two-step mechanism of disentanglement followed by degradation with the first step being predominant at higher concentrations. Mark-Houwink exponent of 0.9002 for the intrinsic viscosity of xanthan gum compared favorably with reported values in the literature. The model for intrinsic viscosity of a free draining coil yielded an expansion coefficient of 1.2 (independent of molecular weight) and a root mean square radius of unperturbed chain in the range of 189.5-368 nm. The root mean square unperturbed chain length increased with molecular weight without reaching an asymptotic value, thus indicating that the xanthan molecule behaved as a stiff chain.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D011135	Polysaccharides, Bacterial	Polysaccharides found in bacteria and in capsules thereof.	Bacterial Polysaccharides
D002236	Carbohydrate Conformation	The characteristic 3-dimensional shape of a carbohydrate.	Carbohydrate Linkage,Carbohydrate Conformations,Carbohydrate Linkages,Conformation, Carbohydrate,Conformations, Carbohydrate,Linkage, Carbohydrate,Linkages, Carbohydrate
D002626	Chemistry, Pharmaceutical	Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.	Medicinal Chemistry,Chemistry, Pharmaceutic,Pharmaceutic Chemistry,Pharmaceutical Chemistry,Chemistry, Medicinal
D004337	Drug Carriers	Forms to which substances are incorporated to improve the delivery and the effectiveness of drugs. Drug carriers are used in drug-delivery systems such as the controlled-release technology to prolong in vivo drug actions, decrease drug metabolism, and reduce drug toxicity. Carriers are also used in designs to increase the effectiveness of drug delivery to the target sites of pharmacological actions. Liposomes, albumin microspheres, soluble synthetic polymers, DNA complexes, protein-drug conjugates, and carrier erythrocytes among others have been employed as biodegradable drug carriers.	Drug Carrier
D012212	Rheology	The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.	Flowmetry,Velocimetry,Velocimetries
D013227	Steam	Water in its gaseous state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Water Vapor,Steams,Vapor, Water,Vapors, Water,Water Vapors
D013242	Sterilization	The destroying of all forms of life, especially microorganisms, by heat, chemical, or other means.
D014783	Viscosity	The resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Viscosities
D019999	Pharmaceutical Solutions	Homogeneous liquid preparations that contain one or more chemical substances dissolved, i.e., molecularly dispersed, in a suitable solvent or mixture of mutually miscible solvents. For reasons of their ingredients, method of preparation, or use, they do not fall into another group of products.	Pharmaceutic Solutions,Solutions, Pharmaceutical,Solutions, Pharmaceutic