Page 66 - Assurance of Sterility for Sensitive Combination Products and Materials

Aseptic processing 53

or positioning the activity so that the airflows from the HEPA filter to the
sterile entity without the air interacting with the potentially contaminated
object (see illustration in Fig. 4.2).
Aseptic practices rely, on clean air surrounding the sterile product and
product contact surfaces, directed airflow, good process design, clean sur-
faces, and proper aseptic technique. The qualification of aseptic practices
should address all variables that could adversely affect sterility. For example;
the variables associated with clean areas might include the capability and
integrity of HEPA filters, differential pressure, and air changes. The variables
associated with directed airflow might include unidirectional airflow, air
velocity, interference, and turbulence. The variables associated with process
design might include ergonomics, equipment design, operator access, and
barriers. The variables associated with clean surfaces might include porous
surfaces, seams, reaction to cleaning materials, and limited access. Finally,
variables associated with aseptic technique might include gowning, training,
access, excessive exposure, and obstacles.
First air includes air above the working surface. The air below the work-
ing surface, for example below the operator’s waist, is generally considered
to be non-sterile. If the operator’s gloves fall below their waist it assumed
that the gloves are contaminated and must be changed or disinfected with a
proven disinfectant solution (e.g., sterile filtered 70% IPA).

Fig. 4.2 First airflow. (Courtesy of ivtnetwork.com)