Kirsten Lyche Baastad, Norwegian Pharmacy Association
8 August 2007
The author’s conclusion has to be contradicted. The contamination was made possible because of the failed preservation. The only way to ensure microbiological quality of sealed containers with water solution is to preserve the solution, particularly when sterilization or aseptic preparation are not applicable as is the case for this product. More extensive general hygiene, as the producer was imposed, would not solve the problem. Microorganisms are ubiquitous.
At the starting point, the Dent-O-Sept solution had excellent anti-microbial properties, as showed by the authors. That is in contradiction of the fact that the swabs were contaminated. The preservation properties in the finished preparation must have been more or less lost during storage. Proportionally it was a small amount of moisturizing liquid in the containers compared to the amount of swab brush in the product. Inhibition of the preserving agent could occur by absorption, chemical reaction, pH-change etc. The preserving agent, benzoic acid, is only active in solutions with pH below 4,5. Maybe for instance the glue over time would raise the pH in the solution and as a consequence inactivate the preserving agent.
The producer of the Dent-O-Sept swab was instructed to meet the requirements of ‘Medical device Class 1, which includes most non-invasive medical devices according to the European Council Directive 93/42/EEC’. However, this directive is not applicable to containers with water solutions. For such products, quality should be provided by application of the principles established in The European Pharmacopoeia (or USP) and guidelines for production e.g. the EU Guidelines for Good Manufacturing Practice (GMP).
Contradiction to the author's conclution
8 August 2007
The author’s conclusion has to be contradicted. The contamination was made possible because of the failed preservation. The only way to ensure microbiological quality of sealed containers with water solution is to preserve the solution, particularly when sterilization or aseptic preparation are not applicable as is the case for this product. More extensive general hygiene, as the producer was imposed, would not solve the problem. Microorganisms are ubiquitous.
At the starting point, the Dent-O-Sept solution had excellent anti-microbial properties, as showed by the authors. That is in contradiction of the fact that the swabs were contaminated. The preservation properties in the finished preparation must have been more or less lost during storage. Proportionally it was a small amount of moisturizing liquid in the containers compared to the amount of swab brush in the product. Inhibition of the preserving agent could occur by absorption, chemical reaction, pH-change etc. The preserving agent, benzoic acid, is only active in solutions with pH below 4,5. Maybe for instance the glue over time would raise the pH in the solution and as a consequence inactivate the preserving agent.
The producer of the Dent-O-Sept swab was instructed to meet the requirements of ‘Medical device Class 1, which includes most non-invasive medical devices according to the European Council Directive 93/42/EEC’. However, this directive is not applicable to containers with water solutions. For such products, quality should be provided by application of the principles established in The European Pharmacopoeia (or USP) and guidelines for production e.g. the EU Guidelines for Good Manufacturing Practice (GMP).
Competing interests
No