Silver-based inorganic
antibacterial agent "Apacider"

Preservatives-effectiveness test

The preservation efficacy of Apasider AW-N and C and phenoxyethanol, a typical preservative, was evaluated and compared microbiologically by the following tests.

【Test method】
Test bacterial species are forcibly inoculated and mixed in the solution containing the test target, and the change of the test bacteria over time is confirmed.
Analysis organization: Marusan Pharmaceutical Biotech Co., Ltd.

Test species

Inoculum count (cfu / g)

E. coli 1.4 × 106
Pseudomonas aeruginosa 8.3 × 105
Staphylococcus aureus 7.3 × 105
Candida 5.7 × 104
Aspergillus 5.9 × 104


Composition of test solution

Compounding amount (%)

AW-N or C



0.1, 0.01

Thickener *) 0.2
water The rest

* Use a thickener to homogenize the formulation.


【Evaluation criteria】

Judgment criteria for various microorganisms based on the Japanese Pharmacopoeia are shown below.


Judgment criteria

14 days later


Less than 1% of the number of inoculated bacteria


The same level as the number of inoculated bacteria or less


【Evaluation results】
Compared to a typical preservative (phenoxyethanol), Apacider C and AW-N were confirmed to have excellent antiseptic effects on various bacterial species other than Aspergillus oryzae at concentrations of 0.1% and 0.01%.

Strong antiseptic effect ○ Appropriate antiseptic effect × Insufficient antiseptic effect

Antibacterial agent

E. coli

Pseudomonas aeruginosa

Staphylococcus aureus













From the above test results, Apasider AW-N and C showed the following superior storage efficacy compared to phenoxyethanol.

1. About 100 times more preservative effect of phenoxyethanol against E. coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida and Aspergillus (preservative effect equal to or better than 1/10 of phenoxyethanol)

2.Appropriate antiseptic effect against Escherichia coli, Staphylococcus aureus and Aspergillus niger with small addition amount (0.01%)

3.Strong antiseptic effect against Pseudomonas aeruginosa and Candida at small addition (0.01%) 

Preservation efficacy test for each bacterial species