The greatest source of contamination in any clean room is the operator [15]. He or she spreads micro-organisms directly into the surrounding air and either directly or indirectly onto surfaces in the room. This can be minimised by the operator donning suitable clean room clothing such as non-shedding suits or coats (depending on the EU Grade of environment), hair cover, shoe covers or dedicated clean room shoes, gloves, and a mask covering the nose and mouth.

The operator remains a source of microbiological contamination, nonetheless, and so aseptic technique is important to protect the product [16]. The principle is to avoid direct contact between the operator and the product (non-touch technique) and hence it is essential to have suitably trained operators whose competency is regularly assessed and who are appropriately supervised.

Before any aseptic activity, hands should be thoroughly washed and disinfected, usually with an alcohol-based gel. The skin flora is both transient and resident. Resident flora is difficult to remove, so it is recommended to always use gloves within the clean room suite. Whilst carrying out aseptic handling in a Grade A environment, sterile gloves are required.

The working area is the immediate environment in which the aseptic handling is performed. It is the working surface (EU Grade A zone) of the LAF or safety cabinet or isolator.

The background area is the room in which the LAF or safety cabinet, or isolator is housed. In the case of open-fronted cabinets there is a distinction in background requirements between the different guidelines mentioned before. The PIC/S guide [2] and the German ADKA guideline [9] require at least EU Grade C, the Dutch hospital pharmacy GMP [8] at least EU Grade D and the requirements in the UK are harmonised with Annex 1 of EU GMP, i.e. Grade B. For isolators the requirement for the background in all guidelines is at least Grade D [1].

Reference is made to Sect. 28.​3 for more information on clean rooms, LAF cabinets, safety cabinets and isolators.

A relevant therapeutic group of active substances, handled aseptically, are parenteral antineoplastics. Many are classified as very toxic for the operator, mainly because of carcinogenicity and reprotoxicity [17], see also Sect. 26.​3.​3. Therefore, if antineoplastics are involved in aseptic handling, requirements are not only to protect the product against contamination of micro-organisms, but also to protect the operator and the environment from the product. The first measure however is a working procedure to minimise exposure to antineoplastics. This involves

To protect the operator and the environment, the most effective measure is working in a safety cabinet or in an isolator with underpressure (negative pressure). Ideally the exhausts of these cabinets should be connected to the open air. An isolator gives more protection than an open-fronted cabinet. See Sect. 28.​3.

The safety cabinet or the isolator should be placed in a well-ventilated and classified background room. To protect surrounding rooms from airborne contamination of antineoplastics the USP advises negative pressure in the background room [6]. However, a study in the Netherlands, carried out by the Netherlands Organisation for Applied Scientific Research (TNO) concluded that airborne contamination from a grade D background (overpressure 15 Pa) to the surrounding environment is not a risk issue.

Further protective measures are:

To prevent contamination with residues it is important to know that cross contamination of antineoplastics from one room to another by direct contact (outside of vials, outside of finished products) is a real risk [19, 20]. This risk can be significantly reduced by a validated cleaning procedure for the safety cabinet or isolator and the background room, and by properly packing the finished products before transport to nursing and treatment centres. Additionally a procedure for removing (potentially) antineoplastic-contaminated waste and a procedure on how to handle spillages or in an emergency are important to prevent contamination with residues. Environmental sampling by wipe tests should demonstrate that all those procedures are effective. In the Netherlands and in Germany a surface contamination limit of less than 0.1 ng/cm² is becoming used more and more as a guideline value, see Sect. 26.​5.​4.

Wherever possible, aseptic products should be stored at 2–8 °C. The shelf life depends on the chemical stability of the product and the potential for microbial contamination [6, 8]. In the Netherlands, from a microbiological point of view, a shelf life at 2–8 °C for 1 month for simple and 1 week for complex aseptic handling is acceptable. In the UK, aseptic products made in pharmacy can only be given a shelf life of seven days unless the pharmacy is licensed with the MHRA (Medicines and Healthcare products Regulatory Agency) for these activities.

Medicines produced by aseptic handling are sometimes administered for more than one day (medication cassette, parenteral nutrition etc.). During the administration the product temperature is higher than the storage temperature, which influences the shelf life. Therefore a second period has to be used, the administration period, which is defined as the maximum time from start to the end of the administration. Both, shelf life and administration period for simple and complex aseptic handling at maximum level of product protection as used in the Netherlands are summarised in Table 31.3 [8].

The emphasis on providing the correct level of cleanliness is to ensure that the properly designed and maintained area is clean and dry. Depending on monitoring results, the use of a disinfectant may need to be considered. However, disinfection is difficult to achieve in an area with even small amounts of dirt [21].

Disinfectants and detergents should be monitored for microbial contamination; dilutions should be kept in previously cleaned containers and should only be stored for defined periods unless sterilised. Disinfectants and detergents used in Grades A and B areas should be sterile prior to use.