Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Tablets – lozenges – or pills
Reexamination Certificate
1999-08-05
2001-02-27
Spear, James M. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Tablets, lozenges, or pills
C424S465000, C514S970000, C514S784000
Reexamination Certificate
active
06194002
ABSTRACT:
BACKGROUND OF THE INVENTION
Bupropion hydrochloride is a well-known antidepressant. It is sold in the United States by Glaxo Wellcome Inc. as prompt release tablets under the tradename WELLBUTRIN® and sustained release tablets under the tradename, WELLBUTRIN SR®.
Bupropion hydrochloride is known to be relatively unstable, such that tablets containing bupropion hydrochloride will degrade at an unacceptably high rate unless the tablets are made by a method or using ingredients which result in improved stability.
U.S. Pat. No. 5,358,970 discloses stabilization of bupropion hydrochloride by including in the tablets a stabilizer. The specific stabilizers disclosed are L-cysteine hydrochloride, glycine hydrochloride, ascorbic acid, malic acid, sodium metabisulfite, isoascorbic acid, citric acid, and L-cysteine hydrochloride. L-cysteine hydrochloride and glycerin hydrochloride are said to be most preferred. All of the examples in U.S. Pat. No. 5,358,970 use L-cysteine hydrochloride or glycine hydrochloride as the stabilizer, and, in each example, the process of manufacture includes the steps of dissolving the stabilizer in water and alcohol, using the solution to granulate the bupropion hydrochloride and other ingredients, and then drying the wet mass.
Such a process has the disadvantage of requiring the use of water and alcohol, and requiring the steps of preparing the solution, using the solution to granulate powder, and drying the wet granulated material.
The object of the present invention is to enable stabilization of compositions comprising bupropion hydrochloride by using a stabilizer that is effective when added in dry form, so as to eliminate the need to use water, alcohol or any other solvent, and thus also eliminate the steps of preparing a solution, using the solution to granulate powder, and drying.
DESCRIPTION OF THE INVENTION
It has been found that the inclusion of fumaric acid as an ingredient in solid compositions comprising bupropion hydrochloride results in improved stability, even if the ingredients are mixed in dry form without use of water, alcohol or any other solvent.
Compositions within the scope of the present invention will thus be solid compositions (such as tablets or capsules) comprising bupropion hydrochloride and fumaric acid. A preferred ratio of fumaric acid to bupropion hydrochloride by weight is from about 0.05 to about 2.0. A more preferred ratio is from about 0.1 to about 1.2 and most preferred ratio is from about 0.2 to about 0.8.
Solid compositions in the form of tablets, for example, can be made simply by mixing bupropion hydrochloride and fumaric acid, along with other usual tabletting ingredients, and then compressing the mixture into tablets on a tablet process.
The other usual tabletting ingredients may include and will preferably include a binder, such as, for example, microcrystalline cellulose or hydroxypropyl methylcellulose; a lubricant such as, for example, magnesium stearate or stearic acid, and a glidant such as, for example, colloidal silicon dioxide.
If the flowability of the mixed powder is not adequate for direct compression into tablets, the mixture may be compacted, following which the compacted material will be ground up into free flowing granules. These granules will then be compressed into tablets on a tablet press.
REFERENCES:
patent: 5358970 (1994-10-01), Ruff et al.
Hart, Organic Chemistry, 8th, Ed., p. 274, Jan. 1991.
Nixon & Vanderhye P.C.
Spear James M.
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