Well I could probably 0.2micron filter it, unfortunately that wouldn't remove endotoxins or be a validatable method either. My easy access sterilisation method would be to have the solution gamma irradiated at a 25kGy min dose (nobody really knows whats in the 'lab sample' boxes that go with routine sterilisation orders!) trouble is gamma doesn't remove endotox either (you usually test before to ensure endotox is below a certain level) and gamma degrades the HA.
PS if you're serious PM me, its not like HA is an illeagal substance, is it. Be aware its a real bastard to disolve though, another product a customer had produced by us took 10hrs mixing.