E 463 HYDROXYPROPYL CELLULOSE

Commission Directive 98/86/EC

Synonyms Cellulose hydroxypropyl ether

Definition Hydroxypropylcellulose is cellulose obtained directly from natural

strains of fibrous plant material and partially etherified with hydroxypropyl groups

Chemical name Hydroxypropyl ether of cellulose

Chemical formula The polymers contain substituted anhydroglucose units with the

following general formula: C₆H₇O₂(OR₁)(OR₂)(OR₃), where R₁, R₂, R₃ each may be one of the following:

- H

- CH₂CHOHCH₃

- CH₂CHO(CH₂CHOHCH₃)CH₃

- CH₂CHO[CH₂CHO(CH₂CHOHCH₃)CH₃]CH₃

Molecular weight From about 30 000 to 1 000 000

Assay Content not less than 80,5 % of hydroxypropoxyl groups

(-OCH₂CHOHCH₃) equivalent to not more than 4,6 hydroxypropyl groups per anhydroglucose unit on the anhydrous basis

Description Slightly hygroscopic white or slightly yellowish or greyish odourless and tasteless, granular or fibrous powder

Identification

A. Solubility Swelling in water, producing a clear to opalescent, viscous, colloidal solution. Soluble in ethanol. Insoluble in ether

B. Gas chromatography Determine the substituents by gas chromotography

Purity

Loss on drying Not more than 10 % (105 °C, 3 hours)

Sulphated ash Not more than 0,5 % determined at 800 ± 25 °C

pH of a 1 % colloidal solution Not less than 5,0 and not more than 8,0

Propylene chlorohydrins Not more than 0,1 mg/kg

Arsenic Not more than 3 mg/kg

Lead Not more than 5 mg/kg

Mercury Not more than 1 mg/kg

Cadmium Not more than 1 mg/kg

Heavy metals (as Pb) Not more than 20 mg/kg