Gum modification

Keywords Gum modification, carboxymethylation, carbamoyl ethylation, sulfation, phosphorylation, thiolation, grafting. X-ray powder diffraction, differential scanning calorimetry, rheology... 

S.no. Natural gum Modification Model drug Dosage form Remarks References... 

The preparation of arabinose from various plant products has been repeatedly described in the literature. The most important sources are cherry gum,2 beet pulp,3 and as has recently been shown by the present authors, mesquite gum. The chief advantages of the preparation from mesquite gum are that the material is readily available in large amounts, the process is simple, and the yield comparatively large. The present procedure is a modification of the original method of Anderson and Sands. 

The Cassia angustifolia GaM possesses the potential to become a new source of commercial gum due to its high content in the endosperm (about 50%) and its valuable rheological properties. It was suggested, in a similar way as for other GaMs, for usage as an additive in pharmaceutical formulations [188, 246]. Also the Ipomoea seed gum in its natural form, and after modification by grafting, has the potential to be used as a commercial gum [178]. 

Cherry and Crandall in 1932 (86) used olive oil as substrate with gum acacia as the emufsTfier. This method has served as the basis for a number of modifications that increased the stability of the emulsion, decreased incubation time and gave better precision. When a serum sample is incubated with a stabilized olive oil emulsion, lipase acts at the interface of substrate and water to hydrolyze olive oil into fatty acid plus diglycerides, and to a small extent to monoglycerides and glycerol. The bile salt sodium deoxycholate activates the reaction. These methods measure the liberated fatty acids by titration with a standardized NaOH solution. An indicator such as phenolphatalein, thymolphthalein or methyl red or a pH meter are used to detect the end point. 

W e know of many examples of the effect of impurities of crystallization. In many cases impurities will completely inhibit (2-4) nucleus formation. Reading the literature on this subject impresses one with the frequent occurrence of hydrocolloids as crystal modifiers, particularly where sugar or water is the material being crystallized. The use of gelatin, locust bean gum, or sodium alginate in ice cream is just one example of many practical applications of hydrocolloids in crystal modification. 

Robert L. Davidson Ed., Handbook of Water-Soluble Gums and Resins Stach and Its Modifications, by M. W. Rutenberg, McGraw-Hill Book Comp, New York, 1980 Chapter 22,ISBN 0-07-015471-6. 

The third composition in Table IV seems to be related to the aromatic sulfonate/polycarbonate technology just discussed with some modifications being necessary in order to compensate for the aliphatic nature of the polypropylene (17. 181 substrate. In this case the aromatic sulfonate is replaced with a metal salt (preferably magnesium stearate). A silicone oil and or gum has been added to enhance the intumescent character and a small amount of inert filler and decabromodiphenyl oxide is included probably to improve the molding characteristics of the total composition. Fire retardant compositions with a good surface char can be obtained at total loadings only about half that required for the halogen/antimony oxide composition. 

One of the major problems associated with beneficiation of PGM from sulphide-dominated deposits is the presence of hydrophobic gangues, such as talc, chlorites, carbonates and aluminosilicates. The concentrates produced in most of the Morensky Reef operations (South Africa) varies from 80 to 150 g/t of combined PGM, where most of the contaminants are silicates, aluminosilicates and talc (i.e. up to 60%). The major hydrophobic gangue depressants used are carboxymethyl cellulose (CMC) and different modifications of guar gums. 

The European Pharmacopoeia (Ph. Eur.) has also adopted some of the apparatus designs (12) described in the USP, with some minor modifications in the specifications. Small but persistent differences between the two have their origin in the fact that the American metal processing industry, unlike the European, uses the imperial rather than the metric system. In the European Pharmacopeia, official dissolution testing apparatus for special dosage forms (medicated chewing gum, transdermal patches) have also been incorporated (Table 2 provides an overview of apparatus in Ph. Eur.). 

Gupta, S., Sharma, P. and Soni, P. L. 2005. Chemical modification of Cassis occidentalis seed gum Carbamoylethylation. Carbohydrate Polymers, 59(4) 501-506. 

The patent literature pertaining to the industrial exploitation of guar gum from 1948 to 1962 has been comprehensively collated by Saxena,34 and will not be considered here. Saxena s compilation34 covers more than 70 patents relating to 15 industries, and includes gum extraction and purification, and modification of gum properties. A selection, taken from the literature over the past decade or so, of applications of galactomannans is given in Table VI. It may be seen that guar gum is, indeed, a versatile product. Some of the more im-... 

BRITISH GUM. — Artificial Gum—Torrefied Starch—Dextrin,—Under theso names a modification of stsroh Is known, which is often prepared in the following manner —... 

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