is Peg400 good?

Hey rookie first post here, just wondering what the differences between PEG 300, PEG 400, and PEG 600 is? Looking to make some orals into liquids and seen most require 300, and 600 but all i can get my hands on is 400. Will 400 work or should i keep looking?
Thanks

The chemist speaks:

For applications where Peg 300 was specified - Peg 400 should be fine - the viscosity difference is not significant.

I'm not sure about Peg 600, though - if a formulation is calling for it, it's almost certainly because the particle density is such that it falls out of suspension too quickly in Peg 300, and the more viscous PEG 600 will keep it stable long enough for dispensing. You could *try* Peg 400 - but since it will behave more like Peg 300 than 600, I suspect it might not work as expected.

Doctor9

my isotretinoin recipe called for peg 300, which i used and it worked out fine, but when i ran out, and i could only get peg 400, it worked just as good. I prefer the peg 300, but 400 will get the job done