Publication Date: 2004-Jun-28
The IP.com Prior Art Database
A MULTI-POLYMER APPROACH TO INFLUENCING THE EXTENDED-RELEASE PROPERTIES OF SODIUM HYDROGEN BIS(2-PROPYLVALERATE) TABLETS
Sodium hydrogen bis (2-propylvalerate) is available as coated tablets with extended- release properties. The formulation is prepared in a high-shear mixer and a fluidized bed dryer. Milled granulate then receives a sustained-release coating in the fluidized bed dryer prior to mixing. The tabletted core receives a sustained-release film and/or a cosmetic coating.
The extended-release properties of the tablet are due to the use of a combination of high-viscosity and film-forming polymers. Similarly, hydrophilic polymer groups including polyethylene oxide, hypromellose, hydroxyethyl cellulose and hydroxypropyl cellulose and hydrophobic polymer groups such as ethylcellulose and some of the vinyl acetate copolymers can be inter-mixed in the formulation. These above-mentioned polymer groups can be integrated into the granulate or tablet as matrix-forming and/or as film-coating elements.
The advantage of such a multi-polymer approach is the synergistic use of the wide span of properties exhibited by the different polymer groups. Such a wide-spectrum approach allows maximum control over the extended-release process. Typical amounts of each polymer in the finished tablet range from 4-15% (w/w).
The active ingredient, which is the major component of this tablet, has pronounced physical characteristics which influence the workability of the formulation during tabletting as well as the dissolution behaviour of the final product.
A prominent physical characteristic of this active ingredient is its 'waxiness'. This very distinct texture predominates the entire tablet cores formulation and interferes with its workability - especially during the tabletting process. Waxy buildups on tablet punches can severely affect the quality and appearance of the finished product as well as impede the process itself. Similarly, this waxiness interferes with the smooth application of the coating to the tablet resulting in a grainy appearance. These problems are further compounded by the hygroscopicity of the active material which can further alter the physical properties of the formulation during manufacture.
Coating the granulate with a polymer in a fluidized be...