Short-term bench testing

The testing program for any medical device can be divided into five phases (1) biocompatibility, (2) short-term bench (or in vitro) tests, (3) long-term bench tests, (4) animal (or in vivo) studies, and (5) human clinical studies. For each of these five phases, the type of device and length of time it will be used must be considered in developing test protocols. 

Experiment 1. Short-term analyte and IS bench top (i.e., room temperature or wet ice bath) solution stability. A minimum of one concentration such as ULOQ spiking solution must be tested. Some laboratories require solution stability at standard 2 (which has concentration typically twice of the LLOQ) or LLOQ spiking solution level. Test for minimum 6 h. 

Experiment 2. Short-term matrix bench top matrix stability. Samples should be thawed by the same procedure as is used for study samples. Test for minimum 6 h. 

Benchtop stability (sometimes also referred to as short-term stability) involves evaluation of the stability of the therapeutic during the execution of the assay, for example, testing the limits of time the samples can be on the bench during processing, testing whether the samples can be pretreated (MRD performed) and stored overnight under refrigerated conditions, and so on [25]. 

In addition to the engineering skills and the access to the full range of supporting laboratory capabilities (bench development, in-process, analytical, physical chemistry, microbiology), scaling-up requires a variety of measurement apparatus (e.g., compressibility cell to measure flows through beds of solids at different compression), as well as the frequent assembly of dedicated apparatus or pilot units (e.g., units to measure fouling rates of surfaces over short-term test, small-scale... 

However, in actual test measurements, at what point, if any, can it be said that all the feed passes through the membrane That is to say, does not holdup occur on the upstream pressure side For in any kind of short-term or transient test (say, in what might be called a batch or semi-continuous laboratory or bench-scale test), does a reject phase not exist at any point At any point in time, is there no situation in which the feed that has not yet passed through the membrane constitute a reject phase Only for a long-term, steady-state test—with no reject sidestream—can it truly be said that all the feed passes through the membrane. This sort of long-term test, properly speaking, then provides the true measure of membrane permeability for the components within a mixture. Whether or... 

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