Ball valves, packing in pumps and pockets in flow meters have been identified as sources of contamination. In order to facilitate cleaning and sanitization, manufacturing and filling lines should be identified and detailed in drawings and SOPs. In some cases, long delivery lines between manufacturing areas and filling areas have been a source of contamination. Also, SOPs, particularly with regard to time limitations between batches and for cleaning have been found deficient in many manufacturers. Review cleaning SOPs, including drawings and validation data with regard to cleaning and sanitization.
Equipment used for batching and mixing of oral solutions and suspensions is relatively basic.
Generally, these products are formulated on a weight basis with the batching tank on load cells so that a final Q.S. can be made by weight. Volumetric means, such as using a dip stick or line on a tank, have been found to be inaccurate. In most cases, manufacturers will assay samples of the bulk solution or suspension prior to filling. A much greater variability has been found with batches that have been manufactured volumetrically rather than by weight. Unfortunately, the manufacturer relied solely on the bulk assay.