Inherent interventions. Inherent interventions are operator-performed activities that are an integral part of the process without which the process can either not occur or cannot be adequately controlled. Examples of inherent interventions are: the initial setup of the aseptic process (which is a series of manual interventions to make the equipment ready for use); product and package resupply; monitoring of process operation (i.e., weight or volume checks and in-process environmental sampling); recordkeeping; and any other activity whose execution is needed to keep the process running.

The frequency of inherent interventions is largely fixed by external factors and not subject to significant variation once initially established. The frequency of their execution may be defined in procedures or by operational requirements. The following inherent interventions are a required part of every aseptic process because their absence would prevent its execution:

• The initial aseptic assembly of a fill line in preparation for filling entails essentially the same interventions for each lot (and perhaps for other similar products in the same scale container).
• Component replenishment is a function of line speed and sterilization quantity. Once defined, it should be constant for similar containers and closures.
• The frequency of weight or volume checks is directly linked to the ability of the filling equipment to maintain constant delivery, and is largely fixed by standard operating procedure (SOP).
• Environmental-monitoring frequency is defined in sampling SOPs that are rarely adjusted once established, although excessive monitoring, which generally is associated with regulatory inspections, has little justification.

Inherent interventions are also an integral part of every process simulation and occur at essentially the same rate during a filling process as they would for a product lot with the same container components. Some firms increase the frequency of environmental monitoring during process simulations, but it is safe to say that the execution rate for inherent interventions in a process simulation is nearly the same as that experienced during a product fill for the same container-closure system.**