Hi,

I'm performing a preservative efficacy test on an oil based
pharmaceutical product.
After trying with different preservatives (benzylalcohol, methyl and
propylparahydroxybenzoate, propyl galate, some combinations) and
different concentrations (up to 4 mg methylparahydroxybenzoate, just
to test) the conclusion is always the same: PET test failed.


Now I'm wondering if it's possible the innoculum forms some micels in
the oil, so that the preservative won't be able to do his job?


Any ideas about what is going on, or how to get the test passed?


Best regards


Ace