%0 Journal Article
%T Carboxymethyl Cellulose Acetate Butyrate: A Review of the Preparations, Properties, and Applications
%A Mohamed El-Sakhawy
%A Samir Kamel
%A Ahmed Salama
%A Hebat-Allah Sarhan
%J Journal of Drug Delivery
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/575969
%X Carboxymethyl cellulose acetate butyrate (CMCAB) has gained increasing importance in several fields, particularly in coating technologies and pharmaceutical research. CMCAB is synthesized by esterification of CMC sodium salt with acetic and butyric anhydrides. CMCAB mixed esters are relatively high molecular weight (MW) thermoplastic polymers with high glass transition temperatures (Tg). CMCAB ester is dispersible in water and soluble in a wide range of organic solvents, allowing varied opportunity to the solvent choice. It makes application of coatings more consistent and defect-free. Its ability to slow down the release rate of highly water-soluble compounds and to increase the dissolution of poorly soluble compounds makes CMCAB a unique and potentially valuable tool in pharmaceutical and amorphous solid dispersions (ASD) formulations. 1. Introduction Cellulose is the most abundant regenerated biopolymer in the planet, with annual production of about 5 ¡Á 1011 metric tons. Most of the cellulose is utilized in industry as a raw material in paper production. Only about 4 from 108 million tons of annually produced pulp are used for chemical production [1]. Hydroxyl groups of cellulose can be reacted to form esters or ethers of different physical and chemical properties suitable for various applications [2]. Cellulose derivatives have significant roles in industry; they represent a main source for fibers, textiles, coatings, thermoplastic films, food additives [1], and pharmaceutical technologies [3]. Cellulose derivatives are usually classified as two main classes, esters and ethers, according to the reactant nature. Cellulose derivatives usually contain free hydroxyl groups available for additional treatments to yield mixed esters. The mixed esters have several improved properties over all neat esters. Cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) are the most commercially important mixed esters [4]. Mixed cellulose derivatives with both ester and ether groups could be also attained. Due to their low degree of substitution and high hydrolytic stability, carboxymethyl cellulose can be further esterified with organic acid anhydrides to add either single or mixed ester groups [5]. Cellulose esters in coating compositions improved many properties as hardness, aluminum flake orientation, flow and leveling, redissolving resistance, clarity, and gloss while it reduced dry-to-touch time, cratering, and blocking [6¨C9]. Mixed cellulose derivatives afford the benefits of conventional cellulose esters with a moderate increase in viscosity
%U http://www.hindawi.com/journals/jdd/2014/575969/