Soft compressed tablets

To give some perspective as to the magnitude of the difference between hard and soft compressed tablets, typical hard detergent tablets (such as those produced for automatic dish washing) are compressed at pressures over 40,000 kN/m, whereas soft tablets use pressure as low as... 

Compressed tablets that are composed of several layers require specially adapted presses designed with several fed hoppers. For a two-layer tablet, one granulation is first fed to a die and partially compressed into a soft tablet. The second granulation is added, and the total die components then are compressed fiiUy. Such procedures are used when the tablet ingredients may be incompatible, which requires separate granulations. If needed, a layer of inert ingredient, eg, lactose, is inserted between the two. 

Soft gelatin capsules are not an inexpensive dosage form, particularly when compared to direct compression tablets [3]. There is a more intimate contact between the shell and its liquid contents than exists with dry-filled hard gelatin capsules, which increases the possibility of interactions. For instance, chloral hydrate formulated with an oily vehicle exerts a proteolytic effect on the gelatin shell however, the effect is greatly reduced when the oily vehicle is replaced with polyethylene glycol [3]. 

Materials that do not compress well produce soft tablets. In addition, brittle crystalline materials will yield brittle tablets. Hiestand was the first pharmaceutical scientist to quantify rationally the compaction properties of pharmaceutical powders [23-28], The results... 

Most capsules are filled on piston-tamp machines. These are fully automatic fillers in which pistons or tamping pins lightly compress the individual doses of powders into plugs (sometimes referred to as slugs ) and eject the plugs into the empty capsule bodies. The compression forces are low, often in the range of 50 200 N, or about 50-100-fold less than typical tablet compression forces. Hence, the plugs frequently will have the consistency of very soft compacts and will not be able to be recovered intact from the filled capsule. 

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... 

The technique involves using a preliminary compression step to produce a relatively soft tablet core which is then placed in a large die containing coating material. Further coating material is added and the content compressed. A similar light compression is used for the production of layers and a final main compression step used to bind the layers together. 

Hydroxypropyl starch is a modified starch and has been used in combination with carrageenan in the production of soft capsules. " Hydroxypropyl starch has been used experimentally in hydrophilic matrices, where it was shown to be an effective matrix for tablets designed for controlled-release drug delivery systems. It has also been used experimentally in the production of hydrophilic matrices by direct compression. ... 

In general, the manufacturing process used for the majority of these tablets are the same as those used for humans and are discussed elsewhere (chap. 13, vol. 1). Direct compression and granulation (wet, dry) are both used. Chewable tablets can also be made by these methods or sometimes are molded via excursion and cut into appropriate sizes. The terms chewable tablets and treats are sometimes confusing. One way to classify is to state that chewable tablets that are made by direct or granulation processes are then called tablets. This would be similar to the mannitol-based chewable tablets prevalent for humans. The term treat is used for the more soft tablets that are produced via extrusion or cast molding. 

For oral administration, the active compound is usually integrated in tablets, soft or hard gelatine capsules or coated tablets. As a rule, a tablet is a compressed preparation that contains approximately 5-10% of the active principle, 80%... 

A blister pack or strip is a container with a foil that is shaped so that it can contain separate dosages [26]. An aluminium lidding foil closes the form foil. Blisters are mostly used to package tablets or capsules. For blister packs a form foil of PVC or laminate of PVC/PVDC (polyvinylidene chloride) is used. The form foil is warmed in a blister machine and a mold station makes round or capsule-Uke pockets with compressed air. PVC is permeable to water vapour and therefore not suitable for tablets or capsules that are moisture sensitive. To package such products the PVC form foil should include an outside layer of PVDC. PVDC permeates less water vapour. Dependent on product sensitivity to moisture, different PVDC-thicknesses can be chosen. When complete resistance to water vapour is necessary a form foil that consists of a formable aluminium laminate (consisting of polyamide, soft aluminium and PVC) has to be used. 

Uses Plasticizer for hard fats solvent for lipophilic ingreds., active substances cosmetic emollient coemulsifier, solubilizer, carrier for lipophilic pharmaceuticals (oral, topical, rectal) lubricant In tablets compressing aid In prod, of tablets, compressed sweets dispersant surfactant absorp. promoter bacterlostat filler for hard/soft gelatin capsules release agent and bloavallablllty enhancer for drugs Regulatory DAB 1999, USP/ NF, JCIC... 

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