Sterility test

I want to ask about sterility test for antibiotic sample. The antibiotic is not penicillin or cephalexin that can be neutralize by sterile beta lactamase. I use close system with nylon membrane filter. May I know how to neutralize the antibiotic? I’ve try several times. I’ve use Fluid D 3 x 100ml and 4 x 100ml rinse the membrane filter but I still cannot get the recovery in the medium (TSB and FTM). So what can I do to neutralize the antibiotic (enrofloxacin)?:confused:

As per USP you can go for further washings i.e. not more than five times with 200 ml.