Manufacturing tablet machines

Process ability Surface area, surface free energy, crystal defects, and deformation potential affect compressibility and machineability on high-speed tableting machines with reduced compression dwell times Particle size distribution and shape affect flow properties, efficiency of dry mixing process, and segregation potential Compressibility, flow ability, and dilution potential affect the choice of direct compression as a manufacturing process... 

There are three types of lubricants employed in solid dosage form manufacture. The first class of lubricant is the glidant. The flow properties of a powder can be enhanced by the inclusion of a glidant. These are added to overcome powder cohesiveness. The two other classes of lubricant are antiadherent excipients, which reduce the friction between the tablet punch faces and tablet punches, and die wall lubricant excipients, which reduce the friction between the tablet surface and the die wall during and after compaction to enable easy ejection of the tablet. The level of a lubricant required in a tablet is formulation dependent and can be optimized using an instrumented tableting machine. 

Effervescent tablets are normally produced by machines with external lubrication systems. Most tablet machine manufacturers can add this type of equipment to their rotary machines. Products with a high proportion of acetylsalicylic acid can be manufactured without any traditional lubricants. Consequently, conventional rotary tablet presses can be used. Effervescent acetylsalicylic acid tablets are produced on ordinary high-speed rotary presses at the Pharmacia plant in Helsingborg, Sweden. 

The commercial manufacturing of effervescent products involves controlling air humidity in the production area. Special tablet machines are generally required, and the package is a very important part of the effervescent product. Over-the-counter analgesics have been very successful as effervescent tablets on certain markets. 

Tablets remain one of the most popular dosage forms for consumers. Convenience, portability, and ease of administration are a few of the factors that drive the market for tablets. Pharmaceutical production also favors tablets owing to the low cost of manufacture compared to other dosage forms. To reduce associated costs and balance the limited drug substance available, tablet development usually begins at a small scale. Manual equipment (i.e., Carver press) or a singlestation tablet machine (i.e., F-Press, EKO) may be used to manufacture tablets one at a time. Small-scale rotary tablet presses (e.g., B3B, BetaPress) are usually used for early clinical trials and formulation optimization prior to scaling up onto a production machine (e.g., Fette 2090 or 3090).

Commercial manufacture of tablets is performed almost exclusively on rotary tablet machines due to their higher output. On a rotary machine, the punch and dies are positioned on a rotating turret, and output will depend on the number of stations positioned around the turret and the speed of rotation. Machines are available with anything from 4 stations for a development machine to 79 stations for the largest production machines. All such machines operate using virtually identical principles that are represented in Figure 11.17. 

The importance of powder flow was emphasised in the section on Powder Flow. The formulation should have sufficient flowability to ensure that the appropriate quantity of powder flows into the dies of the tablet machine on a consistent basis. While the tests described for powder flow are useful development tools, the ultimate test of a formulation is the uniformity of weight of tablets manufactured on a production tablet machine. 

The manufacture of compressed dosage forms (Figure 19.19) for pharmaceutical products has been known for over 200 years and it is this process technology, which has been anployed to make by far the vast majority of detergent products in unit dose form. The fundamental aspects of compaction are common to all compacted materials and the tabletting machines nsed by different industries are also basically similar. The standard steps in nniaxial die compaction are as follows ... 

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