Production of low molecular weight ethylcellulose
OwnerMichael Spencerinventor
Life of this patent
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Abstract
Ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 1 to 100 mPa's, measured as a 5 weight percent solution in toluene and ethanol at a volume ratio of 80:20 at 25° C., is produced by depolymerization of an ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 4 to 400 mPa's in the presence of gaseous hydrogen halide to achieve a reduction in viscosity of the ethylcellulose of at least 10 percent.
Claims16
A process for producing an ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 1 to 100 mPa·s, measured as a 5 weight percent solution in toluene and ethanol at a volume ratio of 80:20 at 25° C., which process comprises the step of depolymerizing an ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 4 to 400 mPa·s in the presence of gaseous hydrogen halide to achieve a reduction in viscosity of the ethylcellulose of at least 10 percent.
A process for producing an ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 1 to 100 mPa·s, measured as a 5 weight percent solution in toluene and ethanol at a volume ratio of 80:20 at 25° C., which process comprises the steps of
- a) etherifying alkalized cellulose with ethyl chloride in the presence of an organic solvent to produce an ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 4 to 400 mPa·s and
- b) depolymerizing the produced ethylcellulose in the presence of gaseous hydrogen halide to achieve a reduction in viscosity of the ethylcellulose of at least 10 percent.
(canceled)
An ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 1 to 2.5 mPa·s, measured as a 5 weight percent solution in toluene and ethanol at a volume ratio of 80:20 at 25 C.
(canceled)
A method of preparing a tablet coating or a film for controlled drug release comprising the step of applying an ethylcellulose having an ethoxyl content of from 40 to 55 percent and a viscosity of from 1 to 2.5 mPa·s, measured as a 5 weight percent solution in toluene and ethanol at a volume ratio of 80:20 at 25° C. to an oral solid dosage form.
Dependencies are inferred from the claim text.