Background Major drawbacks of commercially available compounders are expensive prices, large-scale architecture (24 channels), restricted country support, and gravimetric dosing requiring periodically defined densities and flow factors. However, total parenteral nutrition (TPN) is prescribed in weights or moles of ingredients per volume.

Purpose To evaluate the suitability of a dosing unit formerly developed for inkjet printing and biotechnology for pharmaceutical compounding applications

To perform a feasibility study of a low-cost multi-channel compounder

Materials and Methods Applicability and practicability of the device was assessed by a focus group of researchers and practitioners. Criteria were mainly dosing accuracy, material characteristics, flexibility in module assembling, and predictable cost.

Results Features of a novel modularly-assembled multi-channel dosing unit, formerly designed for inkjet and media dosing in printers and bioreactors, were appraised for suitability for compounding applications. The core of the dosing unit consists of multiple autoclavable, chemically resistant, highly precise volumetric dispensing valves. 3 integrated flow rate sensors are used to measure 2 differential pressures, which permits temperature and viscosity-independent dosing (patent P7711CH01). The pressure above the valve amounts to 500 ± 5 mbar. An electronic valve driver controls the valves to microseconds. Media are transferred as single drops of 0.5 µl by a feeder into a mixing chamber. Exact dosing is guaranteed over a wide range, from µl to dl. The valve was successfully tested in field tests with micro bioreactors (patent CH702769A2). A prototype device for preparing all-in-one TPN bags is presently under construction, together with an electronic interface to patient and administration databases. Further options under development are nanodosing, integration of valves and sensors, as well as miniaturisation to obtain an affordable single-use device.

Conclusions The sensor-driven valve is suitable for use in a compounder for individual liquid preparations. The next step of assembling a prototype compounder is ongoing and aims to increase medicine safety of parenteral ready-to-use all-in-one mixtures, e.g. TPN bags in neonatology.

No conflict of interest.