High-pressure is often necessary for the precise dosing of small quantities of high-viscous pharmaceutical products, such as ointments, creams and gels.
These high-pressures are required to fill viscous media through small openings in primary packaging such as syringes, or to optimise thread breakage. Being able to dispense without pulsation is also essential for applications such as supplying extrudates to the extruder using the Hot Melt method or supplying coatings to the spray nozzle. The Pharma Dispenser from ViscoTec is suitable for these applications due to its stability under high-pressure.
Such dispensers are based upon the endless piston principle and belong to the group of rotating positive displacement pumps. The stainless steel rotor moves eccentrically inside an elastomeric stator and through this interaction, chambers are formed. These alternate opening chambers are sealed between each other, which results in a pressure-resistant, linear pump characteristic curve of 0bar-20bar.
An example is the filling of highly viscous semi-solid pharmaceutical products into dosing syringes. Products with viscosities of up to 500,000mPas are filled, bubble-free, through a tapered, thin opening of a Luer connector and into the syringe. The plug is already inserted and is pressed upwards during the filling process by the dispensing pressure. Dosing syringes can be semi-automatically filled without applying vacuum to fit the plug and without melting the product. Shear-sensitive medicines and media containing solids, such as suspensions, are therefore easier to fill.
Due to their risk of thread breakage, highly viscous medical products such as blood separating gels are difficult to fill cleanly and accurately into tubes. The diameter of the thread is reduced to a minimum thanks to the use of the endless piston principle and a thin dispensing needle. This creates a defined breakage of the thread and the tubes can be filled cleanly, accurately and quickly, without contaminating the edges. The resulting measurements are still linear to the number of revolutions of the pump, even while dispensing at pressures of up to 20bar.
The Pharma Dispenser provides the ideal dosing technology for the accurate filling of small quantities or for the pulsation-free conveying of medium to high viscous pharmaceuticals or medical products.