While the ability of packaging systems to contribute leached substances to finished drug products is well established, increasing interest is being focused on the potential contamination of drug substances by plastic materials encountered during their production. The direct contact of such plastic parts (such as tubing, gaskets, filters and temporary storage containers) with the drug substance at some point in its production raises the possibility that plastic-related contaminants (leachables) may be present in the finished drug product. In this study, eight tubing materials potentially encountered in pharmaceutical production facilities, including six silicone materials and two Santoprene materials, were characterized for their extractable substances by static extraction coupled with comprehensive chemical characterization of the resulting extracts. Based on the extractables profiles thus generated, target leachables were identified for each tubing material. The accumulation of these target leachables was studied by subjecting the tubing to dynamic flow, simulated use extractions. The primary organic extractables from the silicone tubing were a homologous series of silicone oligomers, with most of the tubings demonstrating a unique distribution of oligomers. Several of the silicone tubings also possessed extractable dioctyl phthalate and dioctyl adipate. The primary organic extractables from the Santoprene-type tubing included a number of phthalates, a series of alkyl phenols and decomposition products of Irganox-type antioxidants. Inorganic extractables associated with many of the tubings included Ca, Mg, Zn and B. In general, the levels of targeted leachables extracted from the tubing materials under simulated use (flow) conditions was much smaller than the total amount of these leachables in the tubing.