L522-
Ibuprofen 800mg (Rx strength
Advil)
L373-
I am 99% sure that this pill is:
Ibuprofen 400mg (Rx strength Advil)
Perrigo has only made over the counter products up until fairly recently when they moved towards a limited generic Rx drug catalog.
If you would like further confirmation, you can call Perrigo customer service at (866) 634-9120 and they can verify this info for you.