Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Matrices
Reexamination Certificate
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).
Odidi Amina
Odidi Isa
Foley & Hoag LLP
Intellipharmaceutics Corp
Webman Edward J.
LandOfFree
Controlled release formulation containing bupropion does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Controlled release formulation containing bupropion, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Controlled release formulation containing bupropion will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3151122