Part Three – Compounding Pharmacies: Engineering Controls for Sterile Compounding

This is the final article in a series of three that discusses Oklahoma Pharmacy Law Book’s airflow and filtration regulations regarding respiratory safety and product protection equipment for pharmaceutical compounding. This particular entry focuses on compounding sterile products as discussed in “Part 3: Good Compounding Practices for Sterile Products.”

Although this blog is focused on Oklahoma law, the National Association of Pharmacy Boards (NAPB) (, whose members include 50 state boards, has developed a model law for governing pharmacies.
The first article in the series discusses the generic qualities of air flow within cabinets, hoods, and clean rooms noted in the law book.

The second article discusses engineering controls for compounding non-sterile products (Section 535: 15-10-14 of the Oklahoma Pharmacy Law Book).

Good Compounding Practice for Sterile Products. In the law book, Part 3, Good Compounding Practices for Sterile Products lists standards of air purification required for compounding sterile products. According to the law book, examples of compounded sterile preparations include, but are not limited to, “aqueous bronchial and nasal inhalations, baths and soaks for live organs and tissues, injections (e.g., colloidal dispersions, emulsions, solutions, suspensions), irrigations for wounds and body cavities, ophthalmic drops and ointments, and tissue implants.”

In many cases during sterile compounding, a filtered positive-pressure or filtered negative-pressure environment is needed to either help protect the sterile products (positive-pressure) or help protect the pharmacy technician from inhaling hazardous materials (negative-pressure).

In the table below, you’ll find two columns. The first column provides some excerpts from this section of the law book that describe necessary equipment and levels of protection (e.g., laminar airflow workbench, ISO Class 5). Column two provides a detailed international definition of the standard in column one.

IMPORTANT: Sentry Air Systems provides this information as a customer service. The category of material being handled – for example, hazardous, sterile, non-sterile – and nature of the material – liquid, powder, gel, for example — require different types of engineered controls to protect products, people and the work environment. A certified industrial hygienist should be consulted to determine the best configuration of primary and secondary engineering controls for your pharmacy. 

Oklahoma Pharmacy Law Book, Part 3

Definitions of Standard
International Standard 14644-1 [as expressed in permissible number of particles of various sizes in a square meter of air]

Clean room means ISO Class 5
or better

ISO Class 5:
100,000 at 0.1 µm
23,700 at 0.2 µm
10,020 at 0.3 µm
3,520 at 0.5 µm
832 at 1 µm
29 at 5 µm

535:15-10-51 Primary Engineering Control (PEC) means a device or room that provides an ISO Class 5 environment; includes laminar airflow workbenches, CACIs and CAIs.

See above.

Oklahoma Pharmacy Law Book, Part 3

Definition of Standards NSF 2008 NSF/ANSI 49© 


Compounding Aseptic Containment Isolator (CACI); any air exchange with surrounding area requires HEPA filtration as a minimum

Compounding Aseptic Isolator (CAI) means a device designed for compounding; air exchange into the isolator requires HEPA filtration as a minimum

3.14.1 high efficiency particulate air (HEPA) filter – A throwaway, extended/ pleated medium, dry-type filter with the following:

– rigid casing enclosing the full depth of the pleats;

– minimum particulate removal of 99.99% of particles 0.3 μm diameter of (Type C)

– maximum pressure drop of 1.0 in w.g. (250 Pa) when clean and operated at rated airflow capacity

For more information about any of our air purification products, please call a Sentry Air Systems Applications Specialist at 1.800.799.4609, email us at, or fill out this form to receive more information or a quote.