Tablet mechanical

Tablet mechanical properties measured on samples prepared on an instrumented tablet press or compaction simulator are an excellent means to characterize excipients under dynamic conditions (8,9). Meaningful data analyses are best achieved if both tablet preparation and tablet property measurements are performed at carefully controlled conditions using standardized procedures. Such testing in the authors ...

MAGhaler Lactose monohydrate 200-500 Tablet Mechanical Mechanical... 

Tablets Mechanical properties of the cured UPRs with built-in rapeseed oU (RO) and dicyclopentadiene (DCPD). Reprinted from (2004) Fatipec Congr 2 617 [33] with permission ...

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.

Vapor-phase inhibitors are volatile compounds that adsorb onto metal surfaces, and retard or prevent corrosion by a variety of mechanisms (37). Inhibitors such as dicyclohexamine nitrate [3882-06-02] can protect a variety of metals such as steel, aluminum, and tinplate. A number of vapor-phase inhibitors are commercially available as powders or tablets. However, vapor-phase inhibitors attack nonferrous metals to varying degrees, thus the manufacturers recommendations should be checked before appHcation. The system to be protected must be closed to maintain the volatile compound, but objects as large as the interior of an ocean-going tanker have been treated by this technique. 

Tablet press Molding press Pellet mill 10 Up to 1 ton/hr flow and mechanical properties plastic preforms, metal parts, ceramics, clays, minerals, animal feeds...

Tablet samples were pulled according to the same protocol at different times into the conditioning cycle because the same pattern of results emerged repeatedly, enough information has been gained to permit mechanical and operational modifications to be specified that eliminated the observed inequalities to such a degree that a more uniform product could be guaranteed. The groups are delineated on the assumptions that the within-group distributions are normal and the between-group effects are additive. The physicochemical reasons for the differentiation need not be similarly stmctured.

The stamp associated with the extreme hardness values (number 7, Fig. 4.12, left use STAMP.dat with program MULTI) is the next suspect It is identified and inspected on disassembly of the tablet press Due to mechanical wear, the movement of the stamp assembly is such that an above-average amount of granulate drops into cavity number 7, and is thus compressed to the limiting hardness supported by the granulate. The hardness for stamps 4, 8, and 11 tends to be low, and high for 12, but the data is insufficient to come to definite conclusions for these tools. The tablets from these stamps contaminated what would otherwise been a fairly acceptable product. Because... 

Conclusion The problem areas are tentatively identified the formulations department is asked to improve the flow properties of the granulate and thus decrease the weight dispersion. The maintenance department will now have to find a proposal for countering the excessive wear on one stamp. Note On more modem, heavily instmmented and feed-back controlled tablet presses, the described deviations would have become more readily apparent, and mechanical damage could have been avoided. 

Pellets or tablets (1.5-10 mm in diameter), rings (6-20 mm) and multichanneled pellets (20-40 mm in diameter and 10-20 mm high) are used when a high mechanical strength is required. They are produced by compressing a mixture of the support powder and several binders (kaolin day, stearic acid) and lubricants (graphite) in a press. 

For most tablets, it is necessary to overcome the cohesive strength introduced into the mass by compression. It is therefore common practice to incorporate an excipient, called a disintegrant, which induces this process. Several types, acting by different mechanisms, may be distinguished (a) those that enhance the action of capillary forces in producing a rapid uptake of aqueous liquids, (b) those that swell on contact with water, (c) those that release gases to disrupt the tablet... 

Water uptake has been implicated as a mechanism of action for tablet disintegrants. Khan and Rhodes studied the adsorption and absorption properties of various disintegrants [56]. They concluded that the... 

MOLECULAR STRUCTURE. In their attempts to identify the mechanism(s) of action of tablet disintegrants, researchers recently have turned their... 

Some of the more common antifrictional agents are listed in Table 10. Many of these are hydrophobic and may consequently affect the release of medicament. Therefore, lubricant concentration and mixing time should be kept to the absolute minimum. Lubricants may also reduce significantly the mechanical strength of the tablet (see Fig. 12) [29,81]. Stearic acid and its magnesium and calcium salts are widely used, but the... 

Figures 15 and 16 provide a summary of the compression cycles for rotary and single-punch tablet presses. The formation of the tablet compact in these two types of presses mainly differs in the compaction mechanism itself, as well as the much greater speeds achieved with rotary type presses. The single punch basically uses a hammering type of motion (i.e., the upper punch moves down while the lower punch remains stationary), while rotary presses make use of an accordion-type compression (i.e., both punches move toward each other). The former find their primary use as an R D tool, whereas the latter, having higher outputs, are used in most production operations.

All operations take place simultaneously in different stations. Sixteen stations were commonly used in earlier machines with outputs between 500 and 1000 TPM and tablet diameters up to 15 mm. Presses with outputs orders of magnitude greater than the above are now widely available. The dies are filled as they pass beneath a stationary feed frame, which may be fitted with paddles to aid material transfer. The die cavities are completely filled and excess ejected prior to compression. Compression involves the movement of both punches between compression rolls, in contrast to single station operations where only the upper punch effects compression. Ejection occurs as both punches are moved away from the die on cam tracks until the tablet is completely clear of the die, at which point it hits the edge of the feed frame and is knocked off the press. Tooling pressure may be exerted hydraulically, rather than through the use of mechanical camming actions, as is the case with machines produced by Courtoy. 

In order to produce an adequate tablet formulation, certain requirements, such as sufficient mechanical strength and desired drug release profile, must be met. At times this may be a difficult task for the formulator to achieve, due to poor flow and compactibility characteristics of the powdered drug. This is of particular importance when one only has a small amount of active material to work with and cannot afford to make use of trial-and-error methods. The study of the physics of tablet compaction through the use of instrumented tableting machines (ITMs) enables the formulator to systematically evaluate his formula and make any necessary changes. 

ITMs provide a valuable service to all phases of tablet manufacture, from research to production and quality control [109 111]. As a research tool, ITMs allow in-depth study of the mechanism of tablet compaction by measuring the forces that develop during formation, ejection, and detachment of tablets. ITMs can also provide clues about how materials bond,... 

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