Controlled release formulation containing bupropion

Details Controlled release formulation containing bupropion Controlled release formulation containing bupropion

1998-10-05

2003-11-25

Webman, Edward J. (Department: 1617)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Matrices

C424S487000, C424S468000, C424S499000, C424S501000

Reexamination Certificate

active

06652882

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a controlled release formulation for administration of antidepressant drugs such as bupropion to a subject and to antidepressant formulations of improved stability.
BACKGROUND OF THE INVENTION
Bupropion, or (±)-2-(tert-butylamino)3′-chloropropiophenone, is an aminoketone antidepressant. It may be administered in the form of a pharmaceutically acceptable salt, such as bupropion hydrochloride.
Bupropion is extensively metabolised in mammals and on oral administration, only a small portion of the administered dose reaches the systemic circulation intact. For example, the absolute bioavailability of bupropion in mammals such as rats and dogs ranges from 5% to 20%.
It would therefore be useful to employ a controlled release formulation of bupropion.
The stability of bupropion on storage has also been a cause for concern, the compound being subject to hydrolytic decomposition during storage (
Ther. Drug Monit
. (1985), v. 7(y), pp. 447-458; GA (1985), v. 101, pp. 210748e of UX; and
J. Pharm. Sci
. (1980), v. 69, pp. 1206-1209).
Similar problems of active metabolism and storage instability are encountered with many antidepressant drugs.
SUMMARY OF THE INVENTION
It is an object of the present invention to ode a controlled release pharmaceutical formulation containing as active ingredient an antidepressant such as bupropion or a pharmaceutically acceptable bupropion salt, whereby the active ingredient is released over a period of time to provide improved availability of the drug.
It is a further object of the invention to provide controlled release pharmaceutical formulations whereby the active ingredient is released in either a continuous or a pulsatile manner.
In accordance with one embodiment, the invention provides a controlled release pharmaceutical formulation which comprises an effective amount of bupropion hydrochloride and from about 1% to about 70% by weight of a polymer selected from the group consisting of a) at least one uncrosslinked polymer selected from the group consisting of hydroxyethyl cellulose, sodium carboxymethyl cellulose, hydroxypropyl cellulose and hydroxypropylmethyl cellulose; b) at least one crosslinked insoluble polymer; and c) a mixture of (a) and (b).
The formulations of the invention may further comprise a stabilising agent, such as a saturated polyglycolised glyceride. The polyglycolised glyceride may consist of mono-, di- and triglycerides and of mono- and di- fatty acid esters of polyethylene glycol.


REFERENCES:
patent: 3819706 (1974-06-01), Mehta
patent: 4666705 (1987-05-01), DeCrosta et al.
patent: 5240712 (1993-08-01), Smith et al.
patent: 5731000 (1998-03-01), Ruff et al.
patent: 2 134 516 (1984-08-01), None
Walters, S. M., “Influence of pH on Hydrolytic Decomposition of Dimethylpropion Hydrochloride: Stability Studies on Drug Substance and Tablets Using High-Performance Liquid Chromatography”,J. Pharm. Science,69(10): 1208 (1980).
Laizure, S.C. and DeVane, C. L.,, “Stability of Bupropion and Its Major Metabolites in Human Plasma”,Therapeutic Drug Monitoring,7(4): 447 (1985).

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