A new Sephadex™-based method for removing microbicidal and cytotoxic residues when testing antiseptics against viruses: Experiments with a human coronavirus as a model

Abstract

The relative lack of efficient methods for evaluating antiseptic antiviral activity, together with weaknesses in the existing European Standard (i.e. NF EN 14476+A1), underlines the need to seek a new method which could allow a more precise evaluation of the antiseptic antiviral activity of chemical agents. This protocol is based on an original gel-based filtration method, using "in-house" G-25 and G-10 Sephadex columns. This method allows the neutralization of both the activity and the cytotoxicity of a large range of molecules, according to their molecular size, in only 1min. The viral model used was the human coronavirus (HCoV) 229E chosen for (i) its increasing medical interest, (ii) its potential resistance and (iii) its representing enveloped viruses mentioned in the European Standard. First, the protocol was validated and it was demonstrated that it was fully operational for evaluating antiviral antiseptic potentiality and useful to screen potentially antiseptic molecules. Second, chlorhexidine (CHX) and hexamidine (HXM) were assessed for their potential anti-HCoV 229E antiseptic activities. It was demonstrated clearly that (i) HXM had no activity on the HCoV 229E and (ii) CHX showed a moderate anti-HCoV 229E activity but insufficient to be antiseptic.

Human Coronaviruses: Insights into Environmental Resistance and Its Influence on the Development of New Antiseptic Strategies

“…Two other studies conducted in our laboratory concerned the HCoV 229E and its sensitivity to two widely used antiseptics, chlorhexidine and hexamidine, but also to new molecules belonging to the calixarene family [130,131]. In these studies, antiseptic antiviral activities were assayed thanks to suspension tests and the efficacy criterion was a reduction of 4 log 10 , as recommended by the European Standard [122].…”

“…It was then not sufficient to claim an antiseptic anti-HCoV 229E activity. Hexamidine did not show any activity against HCoV 229E [130,131]. These results highlighted the necessity of (i) evaluating the activity of commonly used antiseptics-disinfectants against different viruses, to be sure of their efficiency and to develop a targeted antisepsis, and (ii) developing new active noncytotoxic molecules.…”

“…the tetra-para-sulfonato-calix[4]arene (C[4]S) and the 1,3-bis(bithiazolyl)-tetra-para-sulfonato-calix[4]arene (C[4]S-BTZ) [130,131]. These molecules were attractive targets at first because they did not show any cytotoxicity.…”

“…Evaluation of antiseptic HCoV 229E activity of (a) chlorhexidine (CHX) and (b) the 1,3-bis(bithiazolyl)-tetra-para-sulfonato-calix[4]arene (C[4]S-BTZ) [130,131]. …”

Inactivation of Coxsackievirus B4, Feline Calicivirus and Herpes Simplex Virus Type 1: Unexpected Virucidal Effect of a Disinfectant on a Non-Enveloped Virus Applied onto a Surface

“…Another critical issue was the elimination of disinfectant before virus titration. Therefore, gel filtration columns were used to filter the disinfectant in experiments with viruses applied on a surface, as they can be used to eliminate disinfectant in virucidal assays towards viruses, as previously described [5,23]].…”