Establishing the Effectiveness of Disinfectants in Secondary Pharmaceutical Facilities

The effectiveness of proprietary disinfectants may be established by reference to supplier information. This is the minimum requirement for any organization. Its application must be considered carefully for each disinfectant in each local operating company. The general antimicrobial activities of the active components of proprietary disinfectants are invariably well known, and if supplier information is to be used it must be verified as being applicable to the particular formulation being purchased.

However reliable supplier information may appear, it must be borne in mind that it can only ever be pertinent to the disinfectants activity against standard stock cultures from culture collections. It can be expected that some regulatory bodies may challenge the adequacy of this information on the basis of a failure to address the effectiveness of the disinfectants against the actual microorganisms likely to be present in the areas where the disinfectants are to be used. In such regulatory climates, the effectiveness of disinfectants must be addressed formally through validation and validation status.

As a general rule it is unacceptable to apply expiry dates without having data available to support them. These data should be obtained in validation, with acceptance criteria that the effectiveness of the disinfectant solution should not have deteriorated significantly during a period of storage equal to or greater than the proposed shelf-life. The containers in which the disinfectants are stored for validation purposes must be the same as those used normally, and the temperature and general conditions of storage must also be those used normally. In order to effectively establish valid expiry dates for disinfectants it is necessary to obtain a base line of their effectiveness when newly prepared.

Both stock cultures and local environmental cultures must be used to validate expiry dates. This data is often available from the supplier. The purpose of validation status checking is to determine if there have been any undetected changes arising over time. It is unlikely that the antimicrobial effectiveness of well-proven antimicrobial actives will change. The most likely source of change is in the contaminating microflora in particular facilities. It is therefore recommended that a formal review is done on the database of environmental microorganisms isolated in a particular facility on a periodic basis (2-years is recommended), and that any new types are included in validation status checks of the effectiveness of the disinfectants on the approved list. The effectiveness of disinfectants may be required to be established for the selection of a new disinfectant, for validation status checking of a previously approved disinfectant, or for the establishment of expiry dates on new or previously approved disinfectants.