Excipients Used in Sustained-Release Formulations

Polyacrylic acid is a commonly used matrix for sustained release formulations. These polymers are available as pharmaceutical grade excipients such as Carbomer 910, 934, 934P, 940, 941, 97IP, and 974P (8). Carbopol (Noveon, Cleveland, Ohio, U.S.A.) polymers are polymers of acrylic acid cross-linked with polyalkenyl ethers or 

In addition to Carbopol, there are other materials used to form sustained-release matrix, including methylcellulose, hydroxypropylmethylcellulose, sodium carboxymethylcellulose (CMEC), carnauba wax, and glyceryl palmitostearate (9,12). 

Materials that form a permeable membrane include fats, bee wax, carnauba wax, cetyl alcohol, cetylsteryl alcohol, zein, acrylic esters, silicone elastomers, and ethylcellulose (14). Aqueous dispersions of water-insoluble polymers are commonly used for sustained-release film coatings. Examples of commercially available aqueous polymer dispersions include Surelease-containing ethylcellulose, Aquacoat-containing 

EXCIPIENTS USED TO ENHANCE DISSOLUTION OF BIOPHARMACEUTICAL CLASSIFICATION SYSTEM CLASS II AND IV DRUGS 

The extent of drug release from oral solid formulations is determined by the dissolution rates of drug, which is a function of aqueous solubility and particle sizes as shown in the following equation. 

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