we are facing problem in formulation of gcsf.it gets precipitated at pH 4.0.Any bright ideas how to go about it?Can it be done at any other pH? Or any other way to bring the pH to 4.0 from 8.0 without precipitation?

I have come across a paper related to dynamics of this phenomenon, it may give a good understanding and reasoning, so that you can get an help.

sry, here iis the paper.