Tablet compressive force

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. 

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

Manufacturing variables (tablet compression force, processing variables, particle size of drug or excipients, and environmental conditions). 

Williams, J.J. Applied Instrumentation Providing Tableting Compression Force. US Patent 4,016,744, 1977. 

Stiel, D.M. Method Invoking Tableting Compression Force Control for Optimizing Tableted Formulation Parameters. US Patent 4,121,289, 1978. 

A simple schematic of a pendulum impact device (PID) is given in Fig. 1. This equipment permits the permanent deformation pressure (H) of a compact of material to be determined [30,31]. Flat-faced tablets of the test substance are compressed at different compression forces and then subjected to impact with a... 

At the other end of the spectrum, many very fine powders are frequently to difficult handle, and may also give rise to hazardous dust clouds when they are transported. It may therefore be necessary to increase the particle size. Examples of size enlargement processes include granulation for the preparation of fertilisers, and compaction using compressive forces to form the tablets required for the administration of pharmaceuticals. 

The effect that compression force can have on the disintegration efficiency seems, therefore, largely dependent on the mechanism of the disintegrant action. The effectiveness of swelling or structure recovery may well be dependent on attaining a compression force that achieves a critical porosity in the matrix. On the other hand, the capillary uptake of liquid, which is a necessary precursor to these mechanisms could be compromised if the tablet matrix is compressed to a porosity too low. 

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). 

Table 2.7 Impact of compression force on photoinstability of nolsidomine tablets...

In pharmaceutical technology research is, among other things, directed to the design of formulations. Considering a tablet system, the physical properties of the formulation depend on the nature and levels of the compounding substances and of the process variables used in manufacturing such as for instance compression force. 

Compression force/hardness profile The compression/hardness profile of a granule batch is an important property. Different subunits of two formulations were selected and compressed using different compression forces in order to obtain tablets. The tablets were tested for hardness as a function of different subrmit numbers (Figs. 11,12). From experience, it is well known that certain formulations show an excellent compression profile as small batches but do not keep this property on the batch size increasing. This is another advantage of the quasi-continuous production concept as, in principle, the quality of the small batch is not changed by the repetitive procedure. 

Figure 22 shows the tablet hardness profiles of the 25 mg strength. Tablet hardness slightly increased as the compression force increased and... 

Granulation particle size did not impact the release rate. In addition, tableting at various compression forces had no significant impact on the release rate of the tablets. This knowledge that variability in tablet manufacture resulted in a uniform sustained release dosage form provided an advantage for further process optimization and scale-up, as shown in Figure 23. 

Subsequent to these successful pilot scale trials, the formulation was scaled-up to the production launch site. Once again, only those parameters recognized as critical were modified during manufacture. The compression parameters that were modified were speed and hardness. A total of four production-sized batches were manufactured, with the first batch being compressed on a 43 station Fette 2080 rotary tablet press, and three subsequent batches compressed on a 36 station Fette 2090 rotary tablet press. Three compression speeds and three compression forces were successfully evaluated... 

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. 

Bilayer compression force (kN) First-layer compression force (kN) Tablet cylindrical height (mm) Tablet hardness (N) Tablet friability (% 500 Drops)... 

During scale-up of a bilayered tablet, it is necessary to determine the range of tamping that can be tolerated for a product. Typically, the tamping force and overall compression force are varied and the tendency to laminate is observed. In addition, the other tablet characteristics are also determined, e.g., hardness, thickness, weight uniformity, disintegration, and dissolution. 

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