Name: Cellulose Acetate
CAS No: Cellulose acetate [9004-35-7], Cellulose diacetate [9035-69-2], Cellulose triacetate [9012-09-3]
BP: Cellulose Acetate PhEur: Cellulose Acetate USP-NF: Cellulose Acetate
Acetic acid, cellulose ester; acetyl cellulose; cellulose diacetate; cellulose triacetate; cellulosi acetas.
Cellulose acetate [9004-35-7], Cellulose diacetate [9035-69-2], Cellulose triacetate [9012-09-3]
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; see Table I.
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.(1–5) 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.(6–8) Cellulose acetate films are used in transdermal drug delivery systems(9,10) and also as film coatings on tablets(11) 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.(2) 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.(12)
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.
See Table II
Density (bulk) Typically 0.4 g/cm3 for powders. Glass transition temperature 170–1908C Melting point Melting range 230–3008C NIR spectra see Figure 1. Solubility The solubility of cellulose acetate is greatly influenced by the level of acetyl groups present. In general, cellulose acetates are soluble in acetone–water blends of varying ratios, dichloromethane–ethanol blends, dimethyl formamide, and dioxane. The cellulose acetates of higher acetyl level are generally more limited in solvent choice than are the lower-acetyl materials. Viscosity (dynamic) Various grades of cellulose acetate are commercially available that differ in their acetyl content and degree of polymerization. They can be used to produce 10% w/v solutions in organic solvents with viscosities of 10–230 mPa s (10–230 cP). Blends of cellulose acetates may also be prepared with intermediate viscosity values
Cellulose acetate is stable if stored in a well-closed container in a cool, dry place. Cellulose acetate hydrolyzes slowly under prolonged adverse conditions such as high temperature and humidity, with a resultant increase in free acid content and odor of acetic acid.
Cellulose acetate is incompatible with strongly acidic or alkaline substances. Cellulose acetate is compatible with the following plasticizers: diethyl phthalate, polyethylene glycol, triacetin, and triethyl citrate
Cellulose acetate is prepared from highly purified cellulose by treatment with acid catalysis and acetic anhydride.
Cellulose acetate is widely used in oral pharmaceutical products and is generally regarded as a nontoxic and nonirritant material.
Observe normal precautions appropriate to the circumstances and quantity of material handled. Dust may be irritant to the eyes and eye protection should be worn. Like most organic materials in powder form, these materials are capable of creating dust explosions. Cellulose acetate is combustible.
Included in the FDA Inactive Ingredients Database (oral tablets). Included in the Canadian List of Acceptable Non-medicinal Ingredients
Cellulose acetate phthalate.
Cellulose acetate is one of the materials that have been selected for harmonization by the Pharmacopeial Discussion Group. For further information see the General Information Chapter <1196> in the USP32–NF27, the General Chapter 5.8 in PhEur 6.0, along with the ‘State of Work’ document on the PhEur EDQM website, and also the General Information Chapter 8 in the JP XV. When solutions are being prepared, cellulose acetate should always be added to the solvent, not the reverse. Various grades of cellulose acetate are available with varying physical properties