Tablets compression-coated

S. Rujivipat, and R. Bodmeier, Improved drug delivery to the lower intestinal tract with tablets compression-coated with enteric/nonenteric polymer powder blends, Eur. J. Pharm. Biopharm., 76 (3), 486-492, 2010. 

Erodings of Slow-Releasing Core Tablets. The sustained-dose portion of a dmg is granulated with hydrophobic materials such as waxes, fatty acids, or fatty alcohols and compressed into a core. The initial dose is added to the core by a modified sugar coating process or by compression coating. Thus, a tablet within a tablet is created. The core erodes slowly to release the active ingredient. 

WA Ritchel, A Sabouni, SH Gehrke, ST Hwang. Permeability of [3H]water across a porous polymer matrix used as a rate-limiting shell in compression-coated tablets. J Controlled Release 12 97-102, 1990. 

Fig. 3—Scanning electron micrograph of the tablet fracture surface from a matrix tablet. Compressive force, 2 kN core coat ratio, 1 1.

Tablet press subclasses primarily are distinguished from one another by the method that the powder blend is delivered to the die cavity. Tablet presses can deliver powders without mechanical assistance (gravity), with mechanical assistance (power assisted), by rotational forces (centrifugal), and in two different locations where a tablet core is formed and subsequently an outer layer of coating material is applied (compression coating).

The most common solid dosage forms of granulated or powdered materials are prepared by compression. Many tablets are coated to minimize the unpleasant taste of certain substances or to protect the ingredients against decomposition and enhance the appearance. 

A. Tablets Compressed powders or granules which form a predetermined shape and weight. Tablets may be coated or uncoated. Excipients include ... 

After tablet compression, content uniformity testing is recommended for each active ingredient, taken from at least three samples of the batch. If coating is included as a process step, the coated tablet would then be tested according to the normal product release testing. In effect, uniformity would not be an issue for the coated core, but it would be important to know that the final product meets its specifications. 

It is also possible to use compression-coating technique to compress a coating around a preformed (relatively soft) core by using a spherical tablet press. The process basically consists of compression of the core to give a relatively soft compact that is then fed into the die of a tablet press that has already received half the coating material. The core is centered within the die, the remainder of the material is added, and the product is compressed.38 An example is Smartrix tablets, in which the release profile of a drug is determined by the increase in release surface caused by erosion (dissolution) of the cover layers.39... 

Sundy, E., and Danckwerts, M. P. (2004), A novel compression-coated doughnut-shaped tablet design for zero-order sustained release, Eur. I. Pharm. Sci., 22,477 485. 

Optimization of more complex compaction operations such as bilayer and trilayer tablets or compression-coated tablets... 

Contents. Note the total number of tablets or other preparation in the container, together with an estimate of the total number which the container could hold if filled. Note the shape (flat, bevelled, biconvex, etc.), whether compression-coated, film-coated, enteric-coated, or sugar-coated, markings (numbers, letters, symbols, or score marks), exterior and interior colour, layered and core tablets, and mean weight, diameter, and thickness. 

Krishnaiah, Y.S. Satyanarayana, S. Prasad, Y.V. Studies of guar gum compression-coated 5-aminosalicylic acid tablets for colon-specific drug delivery. Drug Dev. Ind. Pharm. 1999, 25, 651-657. 

Hariharan, M. Gupta, V.K. Encore a novel compression-coated tablet dosage form. Proceed. Int. Symp. Control. Rel. Bioact. Mater., San Diego, CA, 2001 Controlled Release Society Minneapolis, MN, 2001 6102. 

Glyceryl palmitostearate is used to form microspheres, which may be used in capsules or compressed to form tablets, pellets, coated beads, and biodegradable gels. It is also used for taste-masking. See Table I. 

For some tablets, compression marks the final stage of the production process, but many formulations involve coating the compressed tablet. There are several reasons for applying a coat ... 

---