Why does a carnitine solution is 13% after 2 days?

I suspect that carnitine is stable and so the best solution is sterilization of the solution, filled in a clean bottle in an autoclave. Given that we have to do with a solution in which germ growth can easily occur, the problem should be tackled at the root!

membrane filtation via a sterilized 0.22 µ m filter would also be a possibility if the viscosity is not too high, but for a large volume a larger size of filter is desirable. The filtrated solution should be collected in a sterilized bottle. In order to neutralize the contamination when used, it is appropriate to use Aqua Conservans.