Refrigerated (5C) storage of pharmaceutical research compounds, chemicals, biological samples, and compounded drugs requires highly stable and consistent temperature control, as well as tight temperature uniformity, over long periods of time:

While household or low-end commercial-grade refrigerators are often used for drug and sample storage, few units without high-capacity refrigeration systems, plenum-directed airflow, and high R-value chamber insulation can meet critical sample storage requirements.   Basic 5C storage units often feature lengthy defrost cycle temperature spikes that subject samples to lengthy excursions outside of the specified 2-8C temperature range.  Basic units also feature wide uniformity, stability, and control ranges, which when added up (as occurs in real-world conditions), can lead to areas within those chambers consistently operating out of specification.   Temperature recovery from a door opening, another real-world event, can also be very slow in units without robust cooling capacity and air management, again subjecting product to wide and long temperature deviations.