Inter-laboratory transfer of HPLC methods: Problems and solutions

The Role of HPLC in Technical Transfer and Manufacturing

“…For example, in a procedure that requires an initial sonication step followed by shaking, it was observed that different results were obtained when samples were sonicated for about 30 minutes with an accompanying occasional shaking of the flasks versus a combination of sonication followed by vigorous swirling of the flasks. As much as 3% difference between results was obtained from various studies in the literature [26,[28][29][30]. The type of extraction solvent and the manner or order in which the solvent is added to the sample has also been implicated in differences observed between results from different laboratories.…”

“…For example, clear instructions regarding whether a spike experiment involving the use of pre-prepared samples containing a known amount of the degradation product or the use of samples containing wellcharacterized amount of the degradation product of interest can be stipulated. Also, clear definition of the sample preparation in regard to sonication (power output, water level in batch), shaking, filtration steps, and so on, must be communicated [25][26][27][28][29].…”

“…For example, in the extraction of β-estradiol from tablets, results obtained varied based on how the extraction solvent was added. When the tablets were pre-wetted by the addition of water followed by the addition of the methanol, higher results were obtained than when a premixed extraction solvent of water/methanol was used [29]. Adsorption of analytes on the surfaces extraction vessel (i.e., glass or plastic) is another classical source that contributes to differences in results.…”

“…Follow-up investigation confirmed that the source of the unknown peak initially reported by the receiving lab as degradation peaks was indeed a leachable peak from the nitrile gloves that the chemist wore during the preparation of the samples. Incidents such as this goes to highlight the need to exercise caution in the choice of gloves that can be worn during sample preparation procedures [26,29]. During the execution of sample preparation procedures, care should be taken to avoid spillage of solvents onto gloves, and steps should be taken to replace soiled gloves with new ones.…”

“…The chromatograms in Figure 16-5 show increased formation of two degradation product peaks A and B that occurred in a sample as the sonication time was extended from 20 to 30 minutes. Due to the potential formation of degradation peaks that could contribute to nonagreement between results from different labs, explicit instructions about the duration of the sonication time that should be applied to the samples, power output of the sonicator, level of water in the sonicator, and where samples should be placed within the sonicator should always be provided [26][27][28][29].…”