Where Tableting Technology Is Heading
The tablet making industry is currently going through a period of significant change. An increasing number of patents are expiring giving tool makers and tablet manufacturers plenty of opportunity to innovate in a range of technologies. There is also an increase in the number of manufacturers of generic products and specialists under contract to the large established pharmaceutical companies. Another dynamic force in the business environment is the increase in competition brought about by the opening of markets in developing countries and companies that are relocating their facilities and operations to take advantage of these opportunities.
Consequently there is pressure on tablet manufacturers to provide their clients, both the established pharmaceutical companies, specialist contractors and those who manufacture generic tablets, with equipment that increases production volume and at the same time lowers operating costs.
The need for standards
In 1966 Engineer Swarz (employed by the then Smith Kline French company—presently known as Glaxo Smith Kline) acknowledged that there was a need for international standards for tablet compression tooling in the pharmaceutical industry. At that time he saw a need to develop a compression tool that could be sourced from providers other than the original equipment manufacturer (OEM). At that time, the lead time for purchasing new tooling could exceed 6 months, which significantly extended the time necessary to introduce new products onto the market. The standardization of the tooling that was envisaged in the 1960s and developed in subsequent years has enabled manufacturers to source tooling equipment for various tablet presses in a much shorter time frame.
The American Pharmaceutical Association supported the introduction of standards for tablet making by publishing their standard guideline manual (the IPT manual). The publication, known today as the Tableting Specification Manual or the TSM Standard, is currently in its 7th edition. The manual continues to be one of the leading resources for helping tablet press and tooling manufacturers to specify tablet compression tooling equipment.
After the release of the third edition of the TSM, a British company – I Holland Ltd. realized the need for a European equivalent of the TSM guideline the European community. This led to the introduction of the I Holland Eurostandard which is now the most comprehensive guide available for the standardisation of tablet punches and dies. It is used worldwide for European-built tablet presses. The 2010 edition has been modified to be compatible with the ISO 18084:2005(E) standard.
Unfortunately there are shortcomings with current standards. For example, these fail to address the position of the upper punch key, which is required for shaped tablets such as ovals. The lack of a specification in this instance means that manufacturers can build presses with the key in different positions. This prevents the possibility of interchanging the tooling for common presses. For example, two different manufactures may fabricate the same tooling equipment and follow the “B” format standard assuming they will be interchangeable. The problem is manifest during the ejection cycle of the tablet making process, if the tooling is not interchangeable the punch may not be properly align with the die and consequently the tablets may need to rotate or spin during ejection. This can cause the tablets to accumulate on the die table, leading to damaged tablets and reduced the output. The random keyway could result in high operation costs as many tablet manufacturers may be unaware of the problem. Additional costs may be incurred to overcome the problem by purchasing additional sets of the same tooling equipment. This example clearly shows that there is still work to be done on developing universal standards and the industry, including the tooling vendors and users should support the update to ISO 18084 and help complete the standardization for the key type and location.
Ever increasing production costs and addressing issues such as the keyway problem are examples of what drives innovation in the industry. Such issues also spur refinement and internal organization of the complete manufacturing process. The capital tied up in the machinery asset base is just one cost element for pharmaceutical companies. Equipment efficiency, waste reduction, time to market and the inventory cost of assets should also be taken into consideration as potential areas where innovation could make a big difference.
Another specific example of innovation in tablet making machinery is the Continuous Weight Control System, which allows a tablet to be checked for weight at least once in every turret revolution. As all the stations are checked at the same time, it permits continuous checking of the tablets and ensures that precise weight data is collected and stored for the equipment, thus ensuring that quality is monitored even with tablets that have different shapes and sizes.
When considering improvements in production efficiency, the importance of the human machine interface (HMI), should be recognized which makes it easy to set up a machine. When you consider what factors influence the profitability of a tablet manufacturer, the reduction of waste and improving tablet quality rate highly and can have a greater impact in the long run than the initial capital cost of purchasing the equipment.
Another important factor in relation to costs and profitability is the reduction of production downtime for maintenance and cleaning of equipment. This issue is important to most customers, and it becomes especially relevant to manufacturers that need to reduce their inventory or are interested in a just-in time manufacturing process.
The Synthesis tablet press is a good example of where the experience of Kilian and IMA have been brought together to incorporate the latest customer requirements in terms of efficiency and production optimization. Straightforward operations, simple and fast product set-up in only 6 steps, reproducible quality, robust design and operator friendliness are some of the unique advantages of this machine.
Black spot free tablets, increased run time, rapid cleaning, extended cam and tooling life are guaranteed due to the total isolation of the compression and mechanical areas.
Special seals and silicon bellows are used at this purpose. Additionally a solid stainless steel table isolate the compression area from the lower cam track that is located in a completely separate compartment which is easily accessible.
The tablet chute, the fill shoe and the compression rolls are fixed to pivotal bearings and can swing out ensuring an excellent accessibility and facilitating maintenance and cleaning operations. There is no need of re-adjustment once they are back into position.
The compression rollers are made of special hard steel and this, together with the smooth movement ensured by the new fixing bearings, guarantees longer roller life even with high compression forces. The roller position can be easily modified to change machine configuration for bi-layer and core production. The Synthesis machines feature an interchangeable turret which can be easily removed in few simple steps and positioned on a trolley for cleaning of for changing tooling type.
Innovation and advancement in technology enables companies to stand out against their competitors. The company GEA has developed the Courtoy tablet presses that illustrate how innovation has been embodied in quite novel design features. These features include the ‘extended dwell-time’ at pre and main compression rollers, brought about using a novel air compensator, 'displacement measurement' for highly accurate tablet weight control, independent paddle feeders and enhanced tablet ejection.
But it is perhaps the Exchangeable Compression Module or ‘ECM’ that has revolutionized the machine for fast product changeovers and high containment tabletting of potent tablets, The ECM module is a completely enclosed compression zone within the tablet press that contains all product parts, the turret, punches & dies and isolates the rest of the tablet press from the product.
Enclosing the tablet press within an isolator remains the solution for many press manufacturers, however Courtoy have revolutionised the high containment tablet press market with their unique ECM. Containment performance of the ModulTM is down to less that 1 µg/m³ (with the HC-ECM) during production campaigns within the completely enclosed tablet compression zone of the ECM and with contained loading and unloading methods.
The ECM concept enables very fast change-over times between products, and allows for a reduction in investment for many tabletting plants. Whilst investing in conventional tablet press technology could require buying two tablet presses, just one ModulTM tablet press purchased with two ECMs allowing for fast changeover could produce the same tablet output.
Multi-layer and core tablets
In recent years there has been increasing interest in the fabrication of multi-layer and core tablets and the required manufacturing technology has come a long way as a result of advances in the science associated science, particularly for tablets that have high potencies. Manufacturers of oral drugs are increasing the demand for such multi-layer and core tablet making technology.
Several factors are behind the growing interest in multi-layer tablets rather than conventional single layer tablets. One important factor is that the multi-layer approach is a means of dealing with different drugs that are to be contained within the one package. It is often the case that 2 drugs have formulation matrices that are incompatible with each other. This problem can be solved by using a bi-layer tablet in which the two incompatible matrices are separated by a barrier which prevents the drugs from mixing.
There are actually several advantages of using multi-layer tablets:
a) a multi-layer tablet is a means of combining different drugs in the one form
b) it provides a new distinctive image of tablet for marketing to different consumers
c) it provides a means of differentiating the product from that of competitors
d) because two incompatible drugs do not mix, a multi-layer package can extend the life of the product.
A further enhancement of multi-layer technology is that of core tablets or tablets within tablets. The ability to create multi-layer and core tablets, has had a knock-on effect on the development of inventive formulations. Tablets that were once very difficult to produce are now being commercialized. This includes tablets with either single or multiple doses to be administered together – an ideal solution for elderly patients. Multi-layer innovation also permits the production of modified release tablets, e.g., tablets in which one high potency drug is released in the lower stomach and a further one released lower down the intestinal tract.
To accommodate the increase in the demand for such products, recent developments in core tableting allow machines to do precise tablet core placement, which has been an intractable problem in past years. This new development allows the tablet to be precisely placed and helps tablet designers to determine the dissolution rate before the core is activated. The Elizabeth Companies has designed and patented the Hata Core Tableting Press system, which allows precision core placement and can be used for single, bi-layer, multi-layer and custom core tablets. This feature allows the tablet designer to expand and discover new ways of product development thereby ensuring improvements in solid dosage forms.