Alternative to formaldehyde in fluid preservation of biological specimens

A study had the aim to determine the suitability of biocides used in the pharmaceutical and cosmetic industry to preserve biological specimens. The biocide was assessed according to six parameters: antiseptic range, water/fat solubility coefficient, pH range, stability/reactivity, toxicity and flammability.

A biocide out of range of the present parameters was not considered to be a suitable alternative. First, the substances were assessed according to the technical parameters. The substances that passed these were assessed according to the safety parameters. Twenty-two substances were reviewed according to this process.

The study concluded, that most biocides used in food, cosmetic and pharmaceutical products are not considered to be suitable for preservation of biological specimens. DMDM-hydantoin passes all 6 parameters, but DMDM-hydantoin has never been used for this purpose and therefore its long term effect on the integrity of the specimens is not known.