Single-use hose systems
Using single use hose systems in pharmaceutical and biotechnology applications

The term ‘single-use systems’, or ‘disposal systems’ (systems that can be thrown away), describes systems that are only intended to be used one time and then replaced.

In contrast to this, components made of stainless steel or glass can be reused after they have been properly cleaned.

Single-use systems have the advantage over these reusable systems that the initial investment is lower and also energy costs for cleaning processes (CIP, SIP) can be eliminated.

The parts that come in contact with the product consist of materials approved by the Food and Drug Administration (FDA), such as silicone, polyethylene or polycarbonate. Single-use systems are generally manufactured in class 7 cleanrooms and may also be beta or gamma sterilised, which means that they can be used immediately (ready-to-use systems).

Single-use systems are today used in the majority of biopharmaceutical processes (or ‘bioprocesses’) with animal cell cultures. These processes are divided into upstream and downstream processes.

The upstream process (USP) includes the initial phase in which the microbes/cells, e.g. bacteria or mammalian cell lines, are bred in bioreactors.

This includes all steps associated with inoculum development: media preparation, cell culture and cell separation, as well as harvest. In biotechnology, ‘inoculum’ is the term for the quantity of reproductive cells with which a fermenter is inoculated. When the cells have reached the desired density, they will be harvested and sent into the bioprocess downstream.

Single-use systems have been used widely in the upstream process for many years (e.g. single-use filters, mixers and bioreactors or single-use plastic bags for storage purposes). The downstream process (DSP) covers the part of a bioprocess in which the cell mass from the upstream is processed in order to meet requirements for purity and quality.

The objective of the downstream process is to isolate and purify a biotechnological product in order to create a form suitable for the intended purpose. The end product in this process is typically recovered from an aqueous solution. End products may include, for example, whole cells, organic acids, amino acids, solvents, antibiotics, industrial enzymes, therapeutic proteins or vaccines.

Due to the variety in size and quality of the products, different classification principles are used in recovery and purification. While single-use systems already see widespread use in the upstream process, they have only recently been increasingly used in the downstream process (e.g. single-use bioreactors for microorganisms).

The final step of the downstream process is formulation (the optimal combination of an active ingredient with certain auxiliary ingredients) and filling. Here, single-use systems are used for mixers, transfer systems, dosing systems and filling needles, among other things.

Single-use systems have the following advantages over reusable equipment made of glass or steel:

• shorter production times (no need for sterilisation and purification procedures)
• higher flexibility (product changes can be performed more quickly)
• higher production security (minimised risk of product cross-contamination)
• lower initial investment in a production plant

Some studies also show that the energy costs for purification (CIP, SIP) of permanent systems are currently higher than those of single-use systems. Thus single-use systems have a better carbon footprint.

On the other hand, they have the following disadvantages:

• Single-use systems (especially in the downstream process) frequently form bottlenecks with higher volumes
• the running costs for consumables are much higher
• potential supply chain issues
• large quantities of waste.

Its exceptionally good properties make silicone the material of choice in pharmaceutical applications. The material is relatively soft and can withstand a wide range of temperatures.

Numerous types of silicone are safe to use, meaning they are biocompatible.

Silicones available on the market today differ in both the pharmaceutical approvals and especially the cross-linking process on which their processing is based.