2Melzer E, Kreuter J, Daniels R. Ethylcellulose : a new type of emulsion stabilizer [ J ]. European Journal of Pharma- ceutics and Biopharmaceuties, 2003,56 ( 1 ) : 23- 27.
3Rekhi G S, Jambhekar S S. Ethyl cellulose:a polymer re- view [ J ]. Drug Development and Industrial Pharmacy, 1995,21 ( 1 ) :61-77.
4Bonet M, Quijada C, Cases F. Characterization of ethylce- llulose with different degrees of dubstitution (DS) : a di- ffuse-reflectance infrared study [ J 1. Canadian Journal of Analytical Sciences and Spectroscopy, 2004,49 (4) : 234- 239.
5Zadoreckil P, Hjertbergl T, Arwidsson M. Characteriza- tion of cellulose ethers by 13C NMR (2a) :structural de- termination [J]. Die Makromolekulare Chemie, 1987,188 (3) :513-525.
6Cheng H, English A D. NMR spectroscopy of polymers in solution and in the solid state [ M 1. Washington: Ameri- can Chemical Society,2002:325-335.
7Belcher R, Fildes J E, Nutten A J. The micro and semi- micro determination of alkoxyl groups [ J ]. Analytica Chimica Acta, 1955,13 : 16-22.
8Cobler J G, Smesal E P, Beaver G H. Determination of alkyl cellulose ethers by gas chromatography [ J ]. Talan- ta, 1962,9(6) :473-481.
9The United States Pharmacopeial Convention. United states pharmacopoeia [ M ]. Baltimore: United Book Press, 2007:1118-1119.
10British Pharmacopoeia Commission. British pharmacopoeia [ M ]. London : the Stationery Office,2007 : 821 -$22.