| 摘要 |
<p>A tablet (10) for the controlled release of a drug. The tablet (10) is in the form of an asymmetrically coated tablet so that immediate release or time-delayed release times can be precisely controlled and the extended release slab may provide zero- order or first-order extended release and pulsatile release depending on the excipients used in the tablet formulations. The core (11 ) of the tablet (10) is coated with an asymmetrical coating, that is, a coating with regions (14, 15) having different properties. The coatings may include drugs in varying concentrations. Further, different regions (14, 15) of the coating may have different rates of dissolution. The core (11 ) of the tablet (10) may be provided with a constant cross-sectional area (12) along a longitudinal length of the tablet, a coating having a first region (14) with a more rapid rate of dissolution than a second region (15). The dissolution of the first region (14) exposes only the cross-sectional area (12) to the dissolution medium. The second region (15) of the coating prevents any other portion of the core (11 ) of the tablet from being exposed to the dissolution medium. Therefore, since the cross- sectional area (12) remains constant as it is dissolved, the rate of release of the drug from the core (11 ) of the tablet remains constant. The cross-sectional area (12) may be of any geometrical configuration so long as the area remains constant as the core (11 ) dissolves.</p> |
