Cellulose acetate occurs as a hygroscopic white to off-white, freeflowing powder, pellet, or flake. It is tasteless and odorless, or may have a slight odor of acetic acid.
- BP: Cellulose Acetate
- PhEur: Cellulose Acetate
- USP-NF: Cellulose Acetate
Acetic acid, cellulose ester; acetyl cellulose; cellulose diacetate; cellulose triacetate; cellulosi acetas.
Chemical Name and CAS Registry Number
- Cellulose acetate [9004-35-7]
- Cellulose diacetate [9035-69-2]
- Cellulose triacetate [9012-09-3]
Empirical Formula and Molecular Weight
- Cellulose acetate is cellulose in which a portion or all of the hydroxyl groups are acetylated.
- Cellulose acetate is available in a wide range of acetyl levels and chain lengths and thus molecular weights
Functional Category: Coating agent; extended-release agent; tablet and capsule diluent.
Applications in Pharmaceutical Formulation or Technology
Cellulose acetate is widely used in pharmaceutical formulations both in sustained-release applications and for taste masking. Cellulose acetate is used as a semipermeable coating on tablets, especially on osmotic pump-type tablets and implants.
This allows for controlled, extended release of actives. Cellulose acetate films, in conjunction with other materials, also offer sustained release without the necessity of drilling a hole in the coating as is typical with osmotic pump systems.
Cellulose acetate and other cellulose esters have also been used to form drug-loaded microparticles with controlled-release characteristics. Cellulose acetate films are used in transdermal drug delivery systems and also as film coatings on tablets or granules for taste masking. For example, acetaminophen granules have been coated with a cellulose acetate-based coating before being processed to provide chewable tablets.
Extended-release tablets can also be formulated with cellulose acetate as a directly compressible matrix former. The release profile can be modified by changing the ratio of active to cellulose acetate and by incorporation of plasticizer, but was shown to be insensitive to cellulose acetate molecular weight and particle size distribution. Therapeutically, cellulose acetate has been used to treat cerebral aneurysms, and also for spinal perimedullary arteriovenous fistulas.
Method of Manufacture
Cellulose acetate is prepared from highly purified cellulose by treatment with acid catalysis and acetic anhydride.