I am not sure if I got the question. But, I believe you should do a differentiation process. If you do that in 2-5 days your myoblast will be differentiated in myotubes.
I appreciate your reply and the reference materials provided. After inducing differentiation, the C2C12 cell mixtures still contain some undifferentiated myoblast cells. I am seeking help on how to completely separate these remaining myoblasts from the differentiated myotubes. I am not certain whether there is a feasible method for this. Thank you!