Particle Coating Method Guarantees Precise and Uniform Results with Minimal Losses

With the development of the new Bohle Uni Cone BUC, customers now have a precise method for coating particles as a utility model. “We have shown that our new method works much more accurately and evenly than the conventional Wurster process,” said Managing Director Lorenz Bohle. The Wurster process is used in the pharmaceutical industry when coating small particles, so called pellets. Most coating systems used today are still based on this method, which was developed in 1959.

For L.B. Bohle the biggest weaknesses of the Wurster process are the calculation of scale-up parameters and the location of the spray nozzles inside the product bowl. The scale-up parameters must be verified in multiple and lengthy tests for each product, resulting in a loss of production time and large fluctuations in coating uniformity.

L.B. Bohle developed two major changes that solve both problems of the Wurster process. A sloping floor and a conical tip in the centre provide a uniform movement of product. Simultaneously, the coating substance is delivered from nozzles located tangentially to the product vortex and accessible from outside the product bowl during the process. “Therefore, we reach the best possible coating uniformity. With this process, customers can use active substances with the highest precision,” explained Bohle. “Even in a very complex process, the losses are under one per cent.”  

In addition, the tangential nozzles have enhanced quality advantages in handling. If a nozzle is blocked, it can be cleaned with an aqueous solution during the current process. “Because of the tremendous benefits, we can secure a patent protection for the process and protect the Bohle Uni Cone BUC as a European brand,” concluded Bohle.

Booth 1842, INTERPHEX 2014, 18–20 March 2014, Javits Center in New York City, US.

L.B. Bohle Maschinen + Verfahren GmbH, +49 2524 9323 150, t.borgers@lbbohle.de, www.lbbohle.de.