Hplc

[shankar28]

Is it ok to keep assay and purity method same or not?

[HPLCaddict]

If you're able to validate it, it's valid

Generally speaking, it's usually easier to have separate methods for assay and purity as you can optimize the respective method according to the special needs.
If possible, I'd go for separate methods. At least when it's going into routine usage. During development, a single method for both might be fine.