Coating Technology How to Find the Right Coater for Every Job

Author / Editor: Torsten Meinel-Dirumdam* / Ahlam Rais

Two coater series in comparison, one highly specialised, the other for standard applications  - With coaters from the LC and LC light series, Lödige Process Technology offers two different machine concepts for the film coating of tablets. Pharmaceutical companies therefore have a choice when looking for the optimum task-specific solution. Systems can thus be realized that precisely meet the respective requirements.

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Coater with extended nozzle arm, view from below.
Coater with extended nozzle arm, view from below.
(Source: Gebr. Lödige Maschinenbau GmbH)

Film coating is now one of the standard processes in the pharmaceutical industry. During this process, tablets are coated in a fully perforated drum using the direct current method. The process is divided into three parts: spraying the paint, drying it and then mixing the tablets. Coating in perforated drums impresses thanks to optimal process control, high speeds as well as ease of operation and cleaning.

Drum coating for efficient coating

As a long-standing partner of the pharmaceutical industry, Lödige offers drum coaters in various sizes and designs. All benefit from the manufacturer's process engineering expertise – which ensures an efficient coating process. This is because a large number of variables come into play during the coating process, which have a significant impact on the quality of the result and must be set up competently accordingly.

How do users find the perfect machine for their coating tasks? A few key data can help to answer this question. It is helpful to have a checklist including the following points:

  • Are different product forms (such as tablets, capsules or pellets) to be coated?
  • Is the coating process to take place in a potentially explosive atmosphere?
  • Are there any special containment requirements to be met?
  • Are there any other special features?

The more questions answered with "yes" for the specific application, the more individual the system solution will probably have to be. Lödige has the necessary industry experience to adapt systems precisely to customer requirements and all process conditions.

For challenging coating tasks

The film coaters from the LC series are the solution for challenging applications in the coating of tablets. They can also be used for dosage forms such as capsules, pellets and dragées, just like normal film-coated tablets, and already offer a wide usable volume of 20 to 100 per cent for batch sizes from 0.45 to over 1 ton without modification of the system.

However, the series also offers a very high degree of flexibility beyond throughput – for example for high-containment requirements, to which the entire process can be easily adapted. This ensures that employees and the environment are safely protected. Explosion-proof versions with Atex certification and even special designs such as nitrogen circulation systems are also possible. Users who place particularly high demands on the energy efficiency of their production benefit from options such as a heat exchanger for heat recovery.

As the series has been consistently developed and optimized since its market launch over thirty years ago, it now not only offers a high level of ease of operation and cleaning, but also intelligent process technology with processes that are up to 40 percent faster than other systems.

Alternative for standard applications

For many applications, however, such a degree of specialization is not even necessary. For example, if operators answer all the questions on the checklist formulated at the beginning with a clear "no". Lödige has designed the LC light series for applications with low customization requirements. With its standardized design, the newly developed product family offers an attractively priced alternative to customized machines. No work is required for designing and programming a customized solution.

The performance and scope of the series prove that even a standard can meet high demands: Available in three sizes and equipped with clearly defined but comprehensive functions, the machines offer an efficient solution for both aqueous and organic coating processes. The coaters are insulated all around and offer fully automatic production with integrated recipe management.

The liquid addition with the Manifold system, the determination of the spray rates with a mass flow meter and the swivelling nozzle arm of the coater all indicate the high level of quality. This is supplied by the German specialist manufacturer Düsen-Schlick. A Washing-in-Place (WIP) system is standard on every model in the LC light series. The available options cover the most common coating requirements: They include individual air technology modules, an Atex version and qualification documentation.

Users of the LC light series machines not only benefit from the approximately 40 percent lower investment costs. Delivery times also reflect series production and are significantly shorter than customized versions. In the increasingly dynamic environment of generic production, in which manufacturers must increasingly respond to regional supply bottlenecks and rapidly growing sales markets, this is an advantage with considerable potential.

The right solution for every requirement

Highly specialized or perfected for standard applications – with the LC and LC light series, Lödige offers operators in the pharmaceutical industry the right coater for every application. Both series enjoy a high level of quality for the coating result, which benefits from the supplier's decades of experience with mixing processes: Even with variable filling levels, the mixing elements of the coaters always ensure uniform, gentle mixing – the elementary prerequisite for achieving homogeneous coatings across all batches.

In each version of the two series, the nozzle arms from Düsen-Schlick, which are specially designed to meet the high demands of pharmaceutical production, ensure simple adjustment of the position to the tablet bed so that the distance and angle to the tablet bed represent the process optimum at all times. The specially developed distribution system for the heated supply air ensures perfect drying results within the shortest possible time. When a product changeover is due, both series can be cleaned quickly and reliably without residues using highly efficient cleaning systems – a particular benefit for manufacturers with rapidly changing production cycles and contract manufacturers.

Which version is the right one ultimately depends on the desired application. In order to provide pharmaceutical manufacturers with the best possible support in implementing their requirements and optimizing their processes, the Lödige Pharma Technical Centre offers all the necessary systems for performing comprehensive tests under production-like conditions – in the coating of tablets, pellets or dragées and in other relevant processes such as mixing and sieving. At the end of the process, there is a product that meets all customer requirements, however complex the manufacturing process.

* The author is the Product manager Coater at Gebr. Lödige Maschinenbau, Contact: dirumdam@loedige.de

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