Compression coating

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. 

Where in a product s life a regulation such as TSCA is imposed becomes important in terms of resource diversion. Ideally, imposition of Premanufacture Notification after scale-up and successful line trials would necessitate filing notifications only for those products that actually become commercial. In the usually compressed Coatings and Resins lifeline, this is not always, and in fact very seldom, possible. 

If a biodegradable polymer does not exhibit satisfactory film-forming properties, it may also be used as a compression coat requiring a compaction process onto a drug-containing core [62-64]. 

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).

Compression Coating (This topic is addressed in the Unit Dosing section.)... 

Downstream processing compression, coating (not performed in continuous mode)... 

Materials Granulation Drying Mixing Compression Coating... 

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. 

Sinha, V.R., Singh, A., Singh, S. and Bhinge, J.R. (2007) Compression coated systems for colonic delivery of 5-flurouracil. J Pharm Pharmacol, 59, 359-365. 

Fahie BJ, Nangia A, Chopra SK, et al. Use of NMR imaging in (he optimization of a compression-coated regulated release system. J Control Release 1998 51(2-3) 179-184. 

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