Fast coating of pharmaceutical tablets

Customer needs

The pharmaceutical tablets coating process consists of encapsulating the active substance with sugar syrup in successive coats. It is usually performed in a rotating , heated drum, which usually takes several days, and sometime overheat the product.

Consequently, our customer was looking for a way to greatly speed-up the coating by reinventing the drying process. The solution had to  follow the customer’s scrupulous specifications : as a medication manufacturer, it is essential for the process to be the most rigorous and reproducible.

Main constraints

Due to the delicate nature of the product to be treated, it was necessary not to overheat it by perfectly controlling the power and the distribution of the heating power.

In order not to alter the active principle of the drug, the pills coating must be done without never exceeding 50 °C, while being the closest to this temperature to accelerate the drying process.

Solution proposed

To meet our customer expectations, we designed a rotating drum solution, equipped with a microwave drying system. By directly and smoothly heating the sugar syrup, the process is faster than drying by heated walls.

SAIREM provided a microwave solution at 2450 MHz with a total power of 36 kW,  under a vacuum at 30 mbar. The system is made of 6 generators of 6 kW for a perfect control of the power and distribution of the microwave. Moreover, for hygienic reasons, the  generators are installed in a different room than the coating drum.

Key benefits

Opting for a microwave solution has enabled our client to considerably optimize their capsule coating process:

• This solution saved precious time by reducing the process to only 4 to 6 hours instead of several days
• The percentage of residual moisture after treatment of the product is less than 3%
• The temperature is perfectly controlled thanks to the fine adjustment of the microwave power and diffusion