Step 2: Calculation of AET. Based on information collected in Step 1, the AET can be calculated for each extractable per bag (the SCT of 0.15 µg/day
is being used per PQRI recommendation for OINDP; however, the value could be different for other dosage forms):
Extractables above the AET should be evaluated, but extractables below the AET are of no significant safety or toxicity concern.
Step 3: Design Extraction Conditions. Extraction solvents should include a placebo buffer, a buffer with a lower pH (such as pH 3), and a buffer with a higher pH
(such as pH 9). In addition, an organic solvent (such as methanol, ethanol, or isopropyl alcohol) should be used to cover
a worst-case scenario. For analysis of metals, a dilute acidic solution should be used.
The extraction temperature and time equal 50 °C for 24 hours. The extraction technique is as follows: for the aqueous extraction,
a sealed container is used; for the methanol extraction, reflux is used. For the material/solvent ratio, the important consideration
is the AET. For example, if one bag is extracted with 500 mL of solvent, the AET for the extraction solution is 75 µg/500
mL = 0.15 µg/mL, which is within the analytical detection and quantitation limit of the GC/MS and LC/MS techniques.
Extraction solutions should be analyzed with headspace GC/MS, direct injection GC/MS, and LC/MS (APCI in both positive and
negative modes), as well as with ICP/MS to screen trace metals extractables. Aqueous extractions should be converted to suitable
solvents, such as methylene chloride and hexane for the direct injection GC/MS analysis. The amounts of extractables are quantified
with appropriate standards.
Step 4: Extractables Evaluation. The analytical evaluation should include extractables identity, amount, and potential TDI, as well as a toxicological evaluation.
These evaluations can qualify or disqualify the bag, based on extractables or leachables, from its intended use as a bioprocess
Step 5: Leachables Method Development and Validation. Based on the extractables profile and the profile evaluation, potential leachables are determined and one or more methods
for analyzing the potential leachables are developed. These methods must separate the potential leachables from drug products
such as the active pharmaceutical ingredient (API), additives, and degradants. The methods are validated per ICH guidelines
in terms of method selectivity and specificity, accuracy, precision, linearity, range, and sensitivity.
Step 6: Leachables Analysis of Stability Samples. Leachables are monitored in at least three lots of stability samples at time points of initial, 1, 3, 6, and 12 months, if
Step 7: Leachables Trending, and Extractables and Leachables Correlation Analysis. At the end of the leachables test program, a trending analysis of the leachables should be performed. Additionally, a correlation
analysis of the leachables amount and the extractables amount should be demonstrated. If the leachables are more than the
extractables, the extractables must be revisited.
Step 8: Routine Extractables Method Development and Validation. Based on the extractables profiles, routine extractables methods, which are usually GC/FID or HPLC/UV, are developed and
validated for purposes such as sample preparation. The routine extractables methods should be robust, efficient, exhaustive,
and simple to operate.
Step 9: Bag Release for Use Through Routine Extractables Testing. Different lots of incoming bags should be tested before they are filled with drug solutions. This will ensure that the bags
meet the criteria for potential extractables, and that the bags are suitable for their intended use.