The USP does not provide for dose uniformity testing for oral solutions. Review the firm's data to assure uniformity of fill and test procedures to assure that unit dose samples are being tested. Another problem in the packaging of Oral Liquids is the lack of cleanliness of containers prior to filling. Fibers and even insects have been identified as debris in containers, and particularly plastic containers used for these products. Many manufacturers receive containers shrink-wrapped in plastic to minimize contamination from fiberboard cartons.
Many manufacturers utilize compressed air to clean containers.
Vapors, such as oil vapors, from the compressed air have occasionally been found to present problems. Review the firm's systems for the cleaning of containers.