Tablet compressibility

Tablet Press. The main components of a tablet compression machine (press) are the dies, which hold a measured volume of material to be compressed (granulation), the upper punches which exert pressure on the down stroke, and the lower punches which move upward after compaction to eject the tablets from the dies. Mechanical components deflver the necessary pressure. The granulation is fed from a hopper with a feed-frame on rotary-type presses and a feeding shoe on single-punch presses. A smooth and even flow ensures good weight and compression uniformity. Using the proper formulation, demixing in the hopper is minimized.

Fig. 26 Effect of loading rate on the diametrical breaking strength of tablets compressed at different levels. (From Ref. 123.)...

Hard shell capsules have often been assumed to have better bioavailability than tablets. Most likely this assumption derives from the fact the gelatin shell rapidly dissolves and ruptures, which affords at least the potential for rapid release of the drug, together with the lack of utilization of a compaction process comparable to tablet compression in filling the capsules. However, capsules can be just as easily malformulated as tablets. A number of cases of bioavailability problems with capsules have been reported [5-8],... 

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. 

Matsumara, H., Studies on the mechanism of tablet compression and disintegration. IV. Evolution of wetting heat and its reduction by compressional force, Yakugaku Zasshi, 79 63-68 (1959). 

Effervescent tablets (compressed effervescent powders) do not represent a solid dosage form, because they are dissolved in water immediately prior to ingestion and are, thus, actually, liquid preparations. 

Tablet Compressed herb material in pill form...

Subhngual Tablets Compressed tablets that dissolve under the tongue. 

All tablets compressed with manipulated punches should be discharged by the machine for 100%. 

An advantage of roller compaction is the increase in bulk density resulting in a reduced tablet size. It can also be used to improve the content uniformity of low-dosage compounds. Characteristics which afifect the tabletability of roller compacted formulas include over-lubrication and precompression of the compact. Typically, the powder is roller compacted between 15 and 40 kN of force prior to tablet compression. 

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

Much of the information about compaction can be attributed to the early work in tablet press instrumentation and publications in the general area identified as the physics of tablet compression. For the interested reader, a review of the early history of that work has been published elsewhere [2]. 

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

R2 Results for the tablet compression study R2 without factor Batch 0.2589 0.1040 0.1366... 

Granulation particle size distribution An extremely important parameter that can affect tablet compressibility, hardness, thickness, disintegration, dissolution, weight variation, and content uniformity. This parameter, which can be done by sieve analysis, should be monitored throughout the tablet validation process. 

Let s look at the wet granulation step, for example. We will want to learn whether or not it affects the dissolution of the drug, the final blend performance, the drying and milling procedures, and the final tablet compression performance. If QA is to result from the development effort, answers must be had. The task cannot be left only to the process development scientist to solve, however. Thus, the pragmatic approach to the scientific effort would be that the answer be developed through the partnership of the physical pharmacist, the formula-tor, and the process development engineer (or scientist). 

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. 

The major disadvantages of dry granulation are the reduction in tablet compressibility, formulation-dependent process optimization, and inconsistency of equipment types with respect to the process parameters being measured (e.g., roll force vs roll pressure), thus complicating transfer between equipment types. In spite of these... 

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