## 1 Introduction
In response to these serious events linked to the poor quality of compounded medicines, the Drug Quality and Security Act was published in 2013, giving the FDA more authority to regulate and monitor manufacturers of compounded products [19; 20]. Nowadays, non-sterile and sterile pharmacy preparations, recognized as a fundamental part of pharmacy practice, are subject to strict international quality standards which are legally binding. Compounding pharmacists are obliged to follow them in order to produce safe and effective personal medication [21]. To get a better hold on the preparation of medicines in pharmacies, the European Pharmacopoeia (Ph. Eur. 11) contains the monograph _Pharmaceutical Preparations_[22]. The guidelines of the American Society of Health-System Pharmacists (ASHP) [23] are included in the United States Pharmacopeia (USP) monograph <797> _Pharmaceutical Compounding--Sterile Preparations_[24]. With respect to pharmacy preparations, the USP also contains monograph <795> _Pharmaceutical Compounding--Non-Sterile Preparations_[25] and monograph <1075> _Good Compounding Practices_[26]. To achieve a robust quality of pharmaceutical preparation, adherence to the Good Manufacturing Practice (GMP) guidelines is globally supported. These guidelines should guarantee the proper application and validation of procedures as well as the quality and safety of pharmaceutical preparations [27; 28; 29; 30]. Full compliance with the GMP guidelines is compulsory in both the European Union and the Unites States for outsourcing facilities [1; 19]. The GMP guidelines are especially applicable to high-risk preparations. For low-risk preparations, the PIC/S GPP guidelines [31] are often used as a reference for appropriate quality systems. However, it has been shown that compounding practices for pediatrics that are widely applied in developing countries often lack adherence to these quality guidelines. An important risk factor is a lack of awareness, knowledge, and competence among compounding staff [32]. One of the essential elements of the GMP guidelines (mentioned in GMP Chapter 1) is that Pharmaceutical Quality Systems should facilitate innovation and continual improvement [9]. Quality assurance aspects of the GMP, described in detail in the (recently revised) Annex 1 [33], include the hygiene of compounding personnel. This is crucial for preventing microbial contamination of products, especially those for parenteral administration [34]. Therefore, a globally applied pharmacopoeia requirement is that parenteral dosage forms are sterile [35]. Important in ensuring the quality of sterile medicinal products is the use of cleanrooms, in which microbiological contamination risks are minimized. One of the significant contributors to microbial contamination in cleanrooms are the operators [34]. According to the EU directive 2003/94/EC Chapter 7 (Personnel), it is mandatory to establish and maintain a hygiene program for personnel working in cleanrooms [30]. Also, USP monograph <797> contains numerous requirements in relation to this topic [24]. An essential part of the hygiene program includes hand washing and disinfection procedures. People have been cleaning their hands with water and soap for centuries. Originally, this practice had aesthetic or religious reasons. Following the observation by scientist [PERSON] in 1847 that a correlation existed between maternal mortality and the way doctors cleaned their hands, hand hygiene has also become medically relevant. Hand hygiene has ever since been recognized as the most effective method to prevent the transmission of microorganisms and pathogens [36]. While hand washing is intended to remove particles and visible dirt, disinfection has been proven to be the most effective method for combating the contamination of materials with microorganisms, according to the extensive literature review conducted by the WHO [37]. For both practices, the application technique is essential for achieving optimal results.