The Coating Experts

Optimum solutions for your application

When it comes to quick, trouble-free and efficient coating of tablets, tablet coaters from L.B. Bohle Maschinen und Verfahren GmbH have been setting the benchmark in all areas for many years.

Pharmaceutical film coating is an essential processing step in the production of solids. Tablets are often coated in order to modify how the active ingredient is released, to protect the substance against light or moisture, or to cover a bitter flavor in the tablet formula. Furthermore, tablets are color- or film-coated to facilitate swallowing.

Recently, the processing of active ingredients in the tablet coating - the so-called active ingredient coating - is becoming more and more relevant. It enables the production of combination drugs as well as the combination of two non-compatible active ingredients in one dosage form. In addition, it allows for the combination of different modified-release profiles of the same active ingredient in sustained release tablets. The tablet coating contains the quickly released initial dose while the tablet core contains the slowly released active ingredient. The formulation approaches might consist of up to 4 different coating methods. This leads to long processing times. For the successful development and production of such formulations, tablet coating uniformity is a mandatory requirement.

The optimum interaction of blending, spraying and drying is a crucial factor. All three processes must run simultaneously with the correct settings in order to achieve optimal coating uniformity. Tablet coaters from L.B. Bohle are most advanced in this area. They guarantee the shortest processing times, ensure optimum product results and offer the best combination of the three processing steps on the market.

Blending:

It is essential that the tablet cores move evenly below the spraying cones without causing mechanical load or damage to the tablet cores. The perfect solution is an extended coating pan (length to diameter (L/D) > 1) with the patented welded-in helical baffles from L.B. Bohle. The helical baffles facilitate a constant and careful blending of the flat tablet bed. This reduces the mass pressure inside the tablet bed. The rotating movement of the coating pan generates a radial blending which results in a dead-zone-free tablet bed. Due to the continuous conveying process by means of the twin spirals, the tablets are not subjected to severe accelerations which may otherwise result in tablet breaking or twinning.

Spraying:

Thanks to the pan’s geometry, the largest possible spraying area is achieved within the moving tablet bed. This allows the use of a high number of spraying nozzles. Therefore, tablet coaters from L.B. Bohle, which offer higher spraying rates, reduce the processing time by around 30 percent compared to conventional coaters available on the market with L/D ratios < 1. Besides the quality of the suspension, the nozzle type, the number of nozzles and their distance to the tablets have an influence on the result as well. L.B. Bohle offers different solutions for the adjustment of the distance between nozzle and tablet bed, the spraying angle and the pressure parameters for vaporization.

Drying:

Thanks to an air flow system which differs distinctively from systems offered by competitors, tablet coaters from L.B. Bohle guarantee optimum energy and substance transfer. The process air is fed directly into the tablet bed. Thus, the air flows straight and in a controlled way into the tablet bed and ensures quick drying of the sprayed-on suspension. During the entire process time, the spraying nozzles are not subjected to the supply air flow so that they remain cool during the spraying process. This reduces spray-drying effects to a minimum and achieves coating efficiencies of more than 95 percent. This advantage is particularly relevant for the active ingredient coating as there are fewer spray losses and thus a more uniform tablet coating is achieved.

The optimal coating system for every requirement

The BFC Film Coater is the high-end version of all L.B. Bohle coaters and offers high efficiency, optimal performance and lowest spraying losses. The BFC coater reduces the process time by around 30 percent while achieving excellent coating uniformity. The integrated high-pressure washing system guarantees a cleaning-in-place (CIP) with superior results. BFC coaters can process batch sizes of 50 to 980 liters. Thanks to the similar geometry, scale-up is no problem as with all L.B. Bohle coaters.

The BTC Tablet Coater is synonymous with economical tablet coating. Its main advantages are its simple, space-saving structure and the integrated control cabinet. With the BTC, L.B. Bohle offers an economical system for more efficient and longer processes in the pharmaceutical manufacturing industry.

The BFC Tripan is a particularly versatile system that can be operated with three pans. This allows processing batches of 7 to 75 liters. The pans are quickly and easily changed by means of a lifting device.

L.B. Bohle also offers optimum solutions for research and development. The BFC 5 Laboratory Coater is designed as a stand-alone unit. The entire ventilation technology as well as the electrical and control technology is integrated in the system. Commissioning is quick and easy as only an electrical power supply and a compressed air supply are required. The BFC 5 can be operated with two different pans, which allows the processing of batch sizes of 2 to 13 liters.

With the continuous coater KOCO®, L.B. Bohle meets the increased demand for continuous manufacturing processes. The KOCO® continuous coater is based on the proven patented design of all L.B. Bohle tablet coaters. However, in contrast to all other Bohle coaters, the tablet cores are fed through a product inlet opening on the top of the machine. The process analysis is carried out via an integrated Raman probe. The KOCO® can be incorporated in the production process either alone or as a fully integrated unit of the continuous production system QbCon®.

Containment? No problem!

In recent years, quantity and scope of containment applications have been significantly increasing in the pharmaceutical manufacturing industry. As a matter of course, L.B. Bohle offers the BFC for containment applications as well. The coaters will be designed according to customer specifications and the latest containment requirements. So far, L.B. Bohle is offering containment coaters for OEB levels 1 to 5. The containment coaters come with an automatic nozzle adjustment, infrared product temperature measurement, a connection for cleaning and drying as well as containment flaps, which are integrated in the process control or side doors with inflatable seals.

Slotted Coating Pans for Miniature Tablets

For several years now, miniature tablets have been a common dosage form. They are particularly suited to be used as multi-particle dosage forms as they can be dosed individually and flexibly. Miniature tablets can either be filled into capsules or sachets or applied with miniature tablet dispensers. However, the small cores must be sufficiently stable, which is why they are often coated. The cores are coated particularly gently in a specially slotted coating pan with a corresponding perforation. Not only normal size cores can be coated, but also small cores with a diameter of 1.5 millimeters. Therefore, the system offers maximum flexibility and can be used to process different pellet sizes.