Pharmaceutical manufacturer Dr. Pfleger Arzneimittel is behind well-known OTC brands such as Bio-H-Tin, Ipalat Neuralgin and Mykosert, and also manufactures and markets numerous prescription medicines in the fields of urology, dermatology and pain-relief. What’s less known: In the modern production facility in Bamberg, the company manufactures the products of many well-known domestic and foreign pharmaceutical companies on a contract basis and in accordance with current GMP requirements. Dr. Pfleger Arzneimittel offers services from product development, manufacturing and packaging through to distribution. In addition to tablets, film-coated tablets, capsules, ointments and creams,
the company manufactures and packages suppositories. „We are one of the leading contract manufacturers in this field in
Germany,“ said Martin Schaller, Technical Services Project Manager.
The suppositories are manufactured in a modern moulding process. A 500 l process plant is used for this purpose, in which the suppository mass, consisting of the active ingredient and a fatty base, is melted and transferred via hose bridges to the suppository moulding plant. In the moulding plant, the primary packaging is formed in either plastic or aluminium foil, and the suppository mass is then moulded directly into the cavities. The suppositories are then hardened and sealed in a 105 m long cooling tunnel before being mechanically packaged into cartons.
Production capacity is approximately 20,000 suppositories per hour. As part of this process, a 14 m long ring pipe is used. „The mass is pumped directly from the preparation tank with agitator through heated hose bridges to the suppository filling station,“ explains Martin Schaller. There is no need for an additional moulding vessel, intermediate tank or product funnel. Once at the filling station however, only a small amount is moulded into the cavities; the remainder is pumped back into the preparation tank to repeat the process. Given the repetitive nature of the process, it is particularly important that the temperature is kept constant at 35 to 38 °C. At just two degrees below this value, the mass would harden and settle, and the entire production process could come to a standstill. The homogeneity of the suppository mass and thus the even distribution of the active ingredient could also be affected.
Transferring without pulsation peaks
A positive displacement pump is used to circulate the suppository mass in the ring pipeline. To avoid hardening, the pump must not only be sanitary and efficient enough to process the mass at a viscosity of approximately 4000 to 6000 mPas, but it must be stable and reliable. Of upmost importance is that the pump transfers constantly and without pulsation peaks. High pressure peaks in the volumetric dosing pumps at the filling station could lead to problems with the dosing accuracy. In extreme cases, the uniformity of the suppositories and thus the product quality would suffer. Another criterion: Easy pump maintenance and cleaning. „The pump is rinsed with purified water every night and at the end of a production cycle the pump is disassembled and thoroughly cleaned by a machine. As a result, we require the effort for disassembly and reassembly to be as low as possible,“ says Martin Schaller.
Initially, a rotary lobe pump was used for the important task of recirculating the suppository mass during production. “Not only did the rotary lobe pump have an annoyingly high noise level, but over time its maintenance costs also increased,“ reports Martin Schaller. Recurring leakages led the team at Dr. Pfleger Arzneimittel to look for a more modern alternative. They found what they were looking for at Masosine process pumps, a brand of Watson-Marlow Fluid Technology Group. The requirements for sanitary, reliable low-pulsation pumping at high viscosity, alongside easy and quick manual cleaning meant a sine pump was the optimum solution.
In this type of positive displacement pump, a sinusoidal rotor revolves. This results in four chambers of the same size that shift as a whole – their volume remains unchanged during the process. Inside these chambers, the medium is gently conveyed from the inlet to the discharge port. The seal between the pressure side and the suction side is made by a gate located on the rotor. This simple but effective design makes sine pumps particularly suitable for use at high viscosities of up to 8,000,000 mPas. Certa sine pumps are available in various sizes with a flow rate of up to 99,000 l/h at a maximum pressure of up to 15 bar. Some Certa pump models are self-draining and self-priming. The pump can be used in aseptic processes as it is bacteria-proof and requires no additional steam connections.
EHEDG and 3A certified
Thanks to extensive EHEDG EL Class I Aseptic and 3A certification as well as quick and easy cleaning through CIP and SIP, the Certa sine pump sets the benchmark for hygiene among positive displacement pumps. The pump also offers advantages over other pump types such as rotary lobe pumps, when it comes to manual disassembly and cleaning: Designed with only one rotor, one shaft and one seal, the number of parts in contact with the product is reduced to a minimum. Disassembly and cleaning are therefore much easier and quicker. In addition, this design offers significantly lower energy consumption than comparable positive displacement pumps.
„Compared to our previous rotary lobe pump, the mechanical seal of the sine pump is much easier to access. Unlike the rotary lobe pump, manual cleaning of the mechanical seal can be done with minimal effort. In addition, the static flushing of the seal is much easier to carry out and the seal is also easier to control visually,“ says Martin Schaller.
During comprehensive preliminary tests, the Certa sine pump proved its suitability for use in the production of suppositories at Dr. Pfleger Arzneimittel. During a period of nine months, not a single pump failure occurred. Furthermore, the use of the sine pump has led to a reduction in the noise level in the preparation area. Most importantly: Thanks to the virtually pulsation-free pumping of the viscous mass, the dosing pumps at the filling station work precisely and the suppositories are uniform.
Watson-Marlow GmbH, Rommerskirchen