Opinions on 503B

I am interested in opinions regarding 503B compounding facilities.  Regulations were re-examined revised and put in place to require 503B facilities to follow GMPs after a series of deaths and injuries were traced to a compounding lab.  In the latest regulations though there are exceptions/exemptions. From what I can gather, 503B are restricted in the therapeutics they may compound both by an active list published by the FDA and the additional requirements that the compounded drug cannot be identical to an approved drug nor a simple modification of an approved drug.  

Compounding labs may acquire approved bulk drug substance or final drug product and reformulate by solution in a carrier/solvent other than that used for a manufacturers approved final drug product. They may also combine one or more substances or products to produce a new product.

The last two items in appendix B seem to offer additional benefit to the compounding lab.

"FDA does not intend to take action against an outsourcing facility for failing to conduct batch release testing under 21 CFR 211.165 and 211.167 for biological products that the outsourcing facility repackaged in accordance with the conditions of this guidance and that are assigned a BUD in accordance with Appendix A, provided that the outsourcing facility conducts the following release tests on each batch of biological products that it has repackaged and, except with respect to sterility testing, receives passing results prior to distribution:

o Sterility (the outsourcing facility initiates sterility testing before release and notifies customers of any failing results) o Endotoxin52 o Color o Clarity o Visible particulates o Subvisible particulates"

or

" FDA does not intend to take action against an outsourcing facility for failing to conduct batch release testing under 21 CFR 211.165 and 211.167 for prescription sets that the outsourcing facility prepared in accordance with the conditions described in this guidance, provided that the outsourcing facility conducts the following release tests on each prescription set (at minimum, the first vial) that it has prepared, and it receives passing test results prior to distribution:  

o Sterility

Color

o Visible particulates"

Why is potency, protein content not required for these exemptions? The 503B for biologicals is listed below:

https://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatory...

Thanks for your comments: