The United States Pharmacopeias (USP) has published USP Chapter 797-Pharmaceutical Compounding Sterile Preparations. The USP <797>, enacted Jan 1, 2004 was written to improve the compounding of sterile products. It is the first official and enforceable requirement for compounded sterile preparation (CSP). Specific issues of USP <797> addresses the responsibility of compounding personnel to ensure that CSPs are prepared safely by the means engineering control, which involves primary and secondary control. The primary control can be laminar flow, biosafety cabinet, or isolator, while the secondary control is the room requirement.