PhD defence F.A. (Frits) Boom

Sterility assurance of aseptic handling

Basics, improvements and recommendations

Often, medicines given by an injection must be treated before administration to patients. This can be a simple treatment, such as withdrawing a sterile solution from a vial into a syringe, or a complex treatment where different sterile fluids are mixed together. During the treatment the product must be kept sterile. Both, simple and complex treatments, are called aseptic handling. Simple aseptic handling is mostly performed by nurses in clinical areas (wards). Complex aseptic handling is mostly performed in the hospital pharmacy by trained operators.

The thesis of Frits Boom focusses on reducing the possibility of microbiological contamination of medicines during aseptic handling in hospital pharmacies. In a hospital pharmacy, aseptic handling is performed in a cabinet with a constant sterile air flow. This cabinet as well as all items entering it are potential sources of microbial contamination. He examined the risk of contamination per item by a systematic analysis. Also, measures to reduce these risks were assessed for effectivity by a model described in his thesis. Boom's study made clear that microorganisms mainly enter the cabinet on the surfaces of materials like ampules and vials, even after thorough disinfection. Inside the cabinet, ampoules and vials may contaminate the worktop and the sterile gloves of the operator. Subsequently, the contaminated gloves can contaminate critical spots* through touch and therefore the product. The most important preventive measures are keeping the contamination level of the gloves low and a good ‘aseptic non-touch technique’. Aseptic handling is controlled by microbiological controls. Boom's thesis presents the results of these controls in about 40 hospital pharmacies and describes methods for evaluating and assessing the results. Microbiological controls alone do not cover all sources of contamination. Therefore, he encourages additional controls such as regular operator audits.

*  Critical spots: A surface that may come into contact with a sterile fluid.

Promotors: Prof.dr. D.J. Touw and Dr. R.P.H. le Brun