Which element is NOT part of the stability evaluation for compounded sterile preparations?

The correct choice identifies the duration of compounding as not being part of the stability evaluation for compounded sterile preparations. Stability evaluations are essential to ensure that compounded sterile preparations maintain their potency and safety over time.

The final concentration is vital because it influences the chemical stability of the active ingredients; incorrect concentrations can lead to reduced efficacy or increased toxicity. Container type is also significant, as the material and design of the container can affect the preparation's stability through factors such as moisture permeability and light exposure. The ingredients themselves are crucial in assessing stability, as different substances can interact in ways that may destabilize the compounded preparation.

While duration of compounding is important for aseptic technique and overall patient safety, it does not directly relate to the stability of the compounded sterile preparation. Instead, stability evaluations focus on characteristics such as composition, formulation, and environmental conditions—elements that directly impact how a preparation maintains its integrity over its intended shelf life.