Details for Patent: 6,419,953

Title:	Controlled release formulation of divalproex sodium
Abstract:	The present invention pertains to a hydrophilic matrix tablet suitable for the once-a-day administration of valproate compounds such as divalproex sodium. The tablet comprises from about 50 weight percent to about 55 weight percent of an active ingredient selected from the group consisting of valproic acid, a pharmaceutically acceptable salt or ester of valproic acid, divalproex sodium, and valpromide; from about 20 weight percent to about 40 weight percent hydroxypropyl methylcellulose; from about 5 weight percent to about 15 weight percent lactose, from about 4 weight percent to about 6 weight percent microcrystalline cellulose, and from about 1 weight percent to about 5 weight percent of silicon dioxide; all weight percentages based upon the total weight of the tablet dosage form. Other aspects of the invention relate to the use of this formulation in the treatment of epilepsy and to methods for manufacturing this dosage form.
Inventor(s):	Qiu; Yihong (Gurnee, IL), Poska; Paul Richard (Mundelein, IL), Cheskin; Howard S. (Glencoe, IL), Bollinger; J. Daniel (Libertyville, IL), Engh; Robert K. (Kenosha, WI)
Assignee:	Abbott Laboratories (Abbott Park, IL)
Filing Date:	Dec 18, 1998
Application Number:	09/216,650
Claims:	1. A controller release tablet dosage form comprising: a) a hydrophilic matrix formed from a uniform admixture of: i) about 50 weight percent to about 55 weight percent of an active ingredient selected from the group consisting of valproic sodium acid, a pharmaceutically acceptable salt or ester if valproic acid, divalproex sodium, and valpromide; ii) about 20 weight percent to about 40 weight percent of hydroxypropyl methylcellulose, and iii) about 5 weight percent to about 15 weight percent of lactose; b) from about 4 weight percent to about 6 weight percent of microcrystalline cellulose; c) and from about 1 about 5 weight percent of silicon dioxide; all weight percentages are based upon the total weight of the tablet dosage form. 2. A controlled release tablet dosage form according to claim 1 wherein said active ingredient is divalproex sodium. 3. A controlled release tablet dosage form according to claim 1 wherein said hydroxypropyl methylcellulose is present in an amount of between about 20 weight percent and about 35 weight percent, based on the total weight of the tablet dosage form. 4. A controlled release tablet dosage form according to claim 1 wherein said silicon dioxide has an average particle size ranging between about 1 micron and about 10 microns. 5. A controlled release tablet formulation comprising: a) a hydrophilic matrix formed from a uniform admixture of about 54 weight percent divalproex sodium, about 30 weight percent hydroxypropyl methylcellulose, and about 8 weight percent lactose; b) about 5 weight percent microcrystalline cellulose, and; c) about 3 weight percent silicon dioxide; all weight percentages are based upon the total weight of the tablet dosage form. 6. A granular composition for pressing into a controlled release tablet dosage form, having a particle size ranging between about 0.100 mm and about 0.84 mm comprising: a) a uniform admixture of about 50 weight percent to about 55 weight percent of an active ingredient selected from the group consisting of valproic acid, a pharmaceutically acceptable salt or ester of valproic acid, divalproex sodium, and valpromide, about 20 weight percent to about 40 weight percent of hydroxypropyl methylcellulose, and about 5 weight percent to about 15 weight percent of lactose; b) from about 4 weight percent to about 6 weight percent of microcrystalline cellulose, and c) from about 1 to about 5 weight percent of silicon dioxide; all weight percentages based upon the total weight of the granular composition. 7. The granular composition according to claim 6 wherein said hydroxypropyl methyl cellulose is present in an amount of between about 25 weight percent and about 35 weight percent, based on the total weight of the granular composition. 8. The granular composition according to claim 6 wherein said silicon dioxide has an average particle size ranging between about 1 micron and about 10 microns. 9. A granular composition for pressing into a controlled release tablet dosage form comprising: a) a uniform admixture of about 54 weight percent divalproex sodium, about 30 weight percent hydroxypropyl methylcellulose, and about 8 percent lactose; b) about 5 weight percent microcrystalline cellulose, and; c) about 3 weight percent silicon dioxide, all weight percentages are based upon the total weight of the granular composition. 10. A granular composition for pressing into a controlled release tablet dosage form comprising about 54 weight percent divalproex sodium, about 30 weight percent hydroxypropyl methylcellulose, about 8 weight percent lactose, about 5 weight percent microcrystalline cellulose, and about 3 weight percent silicon dioxide having an average particle size ranging from about microns to about 2 microns to about 5 microns. 11. A method of preparing a granular composition suitable for pressing into a controlled release tablet dosage form comprising the steps of: a) dry blending a mixture of from about 50 weight percent to about 55 weight percent divalproex sodium, from about 20 weight percent to about 40 weight percent hydroxypropyl methylcellulose, and from about 5 weight percent to about 15 weight percent lactose to from a uniform mixture of the dry ingredients; b) wet granulating the dry uniform mixture from step a); c) drying and sizing the wet granules from step b) to select granules having an average size below about 0.84 mm; and d) dry blending the granules with from about 4 weight percent to about 6 weight percent microcrystalline cellulose, and from about 1 to about 5 weight percent silicon dioxide having an average particle size ranging between about 1 micron and about 10 micron. 12. A method of preparing a controlled release tablet dosage form of divalproex sodium comprising the steps of: a) milling bulk divalproex sodium and sizing it to have an average particle size less than about 0.5 mm; b) dry blending a mixture of from about 50 weight percent to about 55 weight percent divalproex sodium, from about 20 weight percent to about 35 weight percent hydroxypropyl methylcellulose, and from about 5 weight percent to about 15 weight percent lactose form a uniform mixture of the dry ingredients; c) wet granulating the dry uniform mixture from step a); d) drying and sizing the wet granules from step b) to select granules having an average size below 1 mm; and e) dry blending the granules with from about 4 weight percent to about 6 weight percent microcrystalline cellulose, and from about 1 to about 5 weight percent silicon dioxide having an average particle size ranging between about 1 micron and about 10 micron; and f) compressing the blended granules of step e) under a force ranging between about 2000 lbf and about 10,000 lbf. 13. The method of claim 12 wherein said silicon dioxide has an average particle size ranging between about 2 microns and about 5 microns. 14. A method of treating epilepsy comprising administering once daily to a patient in need of such treatment a controlled release tablet dosage form according to claim 1. 15. A method of treating epilepsy comprising administering once daily to a patient in need of such treatment a controlled release tablet dosage form according to claim 2. 16. A method of treating epilepsy comprising administering once daily to a patient in need of such treatment a controlled release tablet dosage form according to claim 5.