Ethylcellulose properties

Figure 1. Effect of composition of toluene-ethanol solvent on ethylcellulose properties.

The low-substituted hydroxyethylcellulose which, like methyl- and ethylcellulose, is soluble in alkali, particularly when cooled, has much to recommend it from an industrial point of view. It can be formed by the action of only small quantities (0.25 to 0.5 moles) of ethylene oxide on alkali cellulose.47 The reaction product need not be isolated since there are no salts formed, but may be diluted with water or weak alkali to give a spinning solution. The product should therefore be quite cheap. Preparation and properties of hydroxyethylcellulose have been discussed by Schorger and Shoemaker.47... 

Ethyl butyrate, permeation in selected barrier polymers, 3 389t Ethylcellulose, 4 716, 724t 5 459-461 applications, 5 46 It liquid crystals, 5 385 physical properties, 5 460t production of, 10 590... 

Tarvainen et al. (2002) studied the film-forming ability of starch acetate (DS 2.8) and the effect of commotfly used plasticizers on the physical properties of starch acetate films. The properties were compared with ethylcellulose films. Mechanical studies, water vapor and drug permeability tests, and thermal analysis by differential scarming calorimetry (DSC) were used to characterize the film-forming ability of starch acetate and efficiency of tested plasticizers. Starch acetate films were foimd to be tougher and stronger than ethylcellulose films at the same plasticizer concentration. Also, in most cases, the water vapor permeability of starch acetate... 

While particle size continues to be the physical property most frequently determined by NIR spectroscopy, several other parameters including the dissolution rate and the thickness and hardness of the ethylcellulose coating on theophylline tablets have also been determined using NIR, all with good errors of prediction.94 Tablet hardness, which dictates mechanical stability and dissolution rate, has been determined in hydrochlorothiazide tablets.95... 

When ketoprofen was loaded with chitosan-coated ethylcellulose microparticles and the plain ethylcellulose microparticles, similar findings were obtained. Although ketoprofen is well absorbed from the GI tract, chitosan appears to influence the absorption profile. Chitosan allowed the particles to make contact with the mucosal membrane and be retained at adhesive sites, which means that the drug remains in the small intestine longer. This facilitated the absorption of ketoprofen in chitosan-coated microparticles loaded with ketoprofen. Chitosan is considered to improve the absorption properties of plain microparticles [33]. 

Martinac,A., Filipovic-Grcic, J.,Voinovich, D.,Perissutti, B., and Franceschinis, E. (2005), Development and bioadhesive properties of chitosan-ethylcellulose microspheres for nasal delivery, Int. I. Pharm., 291, 69-77. 

Rheological properties have also been studied. It has been observed for some concentrations that the first difference of normal stress becomes negative for a certain range of shear stress. This effect had already been observed in the case of HPC (2fl). Figure 5 illustrates the case of another cellulosic derivative ethylcellulose. 

Bodmeier, R. Paeratakul, O. The effect of curing on drug release and morphological properties of ethylcellulose pseudolatex-coated beads. Drug Dev. Ind. Pharm. 1994, 20 (9), 1517-1533. 

Aqualon Ethylcellulose (EC) physical and chemical properties. In Technical Bulletin Hercules, Inc. Wilmington, DE, 1996. 

Properties are highly dependent upon the polarity of the substituent. Water-solubility is obtained at a DS value of about 1 for nonionic ethers. If hydro-phobic ether groups predominate, the water solubility may disappear at a DS levels above 2 [5]. Methylcellulose is in fact soluble up to about 1.8, whereas ethylcellulose only up to 1.2—1.4 (not available commercially). Introducing polar groups (carboxyls, hydroxyls) of course strongly increases hydrophilicity. 

Isotherms for the adsorption of phenylureas on ethylcellulose are of the C-type (71) (top of Figure 12). The constant partition or C-type isotherm is common when new sites become available as the solute is adsorbed from the solution. For every concentration of a particular chemical that is used, the same proportionate amount is partitioned between the adsorbent surface and the solution phase. The diflFerence in adsorption of one compound vs. another depends upon the structure and properties of the compounds and the preference by the adsorbent of the compounds over that of water molecules. The phenylureas were readily desorbed from ethylcellulose with water showing that the adsorption mechanism was physical in nature. 

Regression analyses showed that several properties of the phenylureas were correlated with their adsorption by ethylcellulose (fenuron excluded) (Table X). Parachor was the parameter most highly correlated with adsorption of the phenylureas. 

Zetzl AK, Marangoni AG, Barbut S. Mechanical properties of ethylcellulose oleogels and their potential for saturated fat reduction in frankfurters. Food Fund. 3(3) (2012) 327-337. 

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