Guar gum

About: Guar gum is a research topic. Over the lifetime, 5611 publications have been published within this topic receiving 105940 citations.

Development of polysaccharide-based colon targeted drug delivery systems for the treatment of amoebiasis.

Abstract: The main focus of this study is to develop colon targeted drug delivery systems for metronidazole (MTZ). Tablets were prepared using various polysaccharides or indigenously developed graft copolymer of methacrylic acid with guar gum (GG) as a carrier. Various polysaccharides such as GG, xanthan gum, pectin, carrageenan, beta-cyclodextrin (CD) or methacrylic acid-g-guar (MAA-g-GG) gum have been selected and evaluated. The prepared tablets were tested in vitro for their suitability as colon-specific drug delivery systems. To further improve the colon specificity, some selected tablet formulations were enteric coated with Eudragit-L 100 to give protection in an acidic environment. Drug release studies were performed in simulated gastric fluid (SGF) for 2 hr followed by simulated intestinal fluid (SIF) at pH 7.4. The dissolution data demonstrate that the rate of drug release is dependent upon the nature and concentration of polysaccharide/polymer used in the formulations. Uncoated tablets containing xanthan gum or mixture of xanthan gum with graft copolymer showed 30-40% drug release during the initial 4-5 hr, whereas for tablets containing GG with the graft copolymer, it was 70%. After enteric coating, the release was drastically reduced to 18-24%. The other polysaccharides were unable to protect drug release under similar conditions. Preparations with xanthan gum as a matrix showed the time-dependent release behavior. Further, in vitro release was performed in the dissolution media with rat caecal contents. Results indicated an enhanced release when compared to formulations studied in dissolution media without rat caecal contents, because of microbial degradation or polymer solubilization. The nature of drug transport was found to be non-Fickian in case of uncoated formulations, whereas for the coated formulations, it was found to be super-Case-II. Statistical analyses of release data indicated that MTZ release is significantly affected by the nature of the polysaccharide used and enteric coating of the tablet. Differential scanning calorimetry indicated the presence of crystalline nature of drug in the formulations.

Specific Effects of Guar Gum or Gum Arabic on Adaptation of Cecal Digestion to High Fiber Diets in the Rat

Abstract: The objective of this work was to examine whether the nature of fiber may influence the cecal digestion in the rat fed hydrocolloids such as gums. Adaptation to a high fiber diet containing 15% guar gum (GG) or gum arabic (GA) was thus studied in rats previously adapted to a high starch fiber-free diet. Both gums elicited a marked enlargement of the cecum and a trophic effect on the cecal wall. The cecal pH dropped to 5.8, then plateaued to about 6.1. During the first days of adaptation, a part of GA escaped microbial degradation; thereafter the cecal pool of volatile fatty acids (VFA) was similar with both diets (approximately equal to 1000 mumol). GA promoted propionate-rich fermentations, whereas GG rather enhanced acetic and butyric fermentations. VFA absorption was higher with the gum diets than with the control diet, because blood flow increased in parallel to the weight of cecal wall. K+, Mg2+ and Ca2+ were absorbed in large amounts from the cecum, particularly in rats fed the GA diet. With this diet, high concentrations of nonsoluble Ca2+ and phosphate (but low concentrations of soluble phosphate) were found in the cecum. The study indicates that gums have potent effects on digestion in the large bowel, and that there are specific effects of the different types of gums.

Effect of pH and Heat Treatment on the Binding of Calcium, Magnesium, Zinc, and Iron to Wheat Bran and Fractions of Dietary Fiber

Abstract: The effect of pH and heat treatment on the binding of added food grade sources of calcium, magnesium, zinc, and iron to a standard wheat bran, cellulose, and lignin was investigated. 1% solutions of pectin and guar gum were examined for their ability to bind these metals in aqueous solution. Lignin and pectin was found to have high metal binding capacities. Metal binding to fiber was found to be pH dependent. Toasting had no effect on metal binding by cellulose, but had a significant effect on the binding of metals by lignin and wheat bran. Boiling had a significant effect on the binding of metals by cellulose, lignin, and wheat bran.