The United States Pharmacopeia (USP) has recently released an In-Process Revision to Chapter – Pharmaceutical Compounding – Sterile Preparations.1 The Baker Company conducted a study to evaluate its phar- macy isolators using the criteria presented in the In-Process Revision. The results in this paper demonstrate that the SterilSHIELD (compounding aseptic isolator – CAI) and the ChemoSHIELD (compounding aseptic containment isolator – CACI) meet the performance criteria required by the In-Process Revision to USP Chapter when located in an environment worse than ISO Class 7. ISO 5 conditions are maintained when the isolators are challenged with background conditions worse than ISO Class 9. Additionally, these requirements are met without the use of cleanroom garb.