Failure in dispensing right first time may result in a major problem of product quality.

The design, operation, control systems, recording and cleaning of the dispensing department must all be aimed at ensuring that there is no risk of cross-contamination. The procedures, design and operation of the area must ensure that the right material is dispensed in the right quantity for the right product. The segregation, control systems and record-keeping must all be aimed at achieving this result.

The environmental controls for the area must be designed to ensure that the powders are kept within the area. The air handling, pressure differentials, airflow patterns and dust extraction systems need to be designed carefully to provide pharmaceutical quality conditions with good separation from the main warehouse area. As necessary, appropriate microbiological control systems may be required. Weighing should be treated as the second stage in pharmaceutical processing after sampling, with all the requirements being met.

Weighing areas need to be segregated from the main production areas, and from each other to allow flexibility and to permit clean down between materials and products. If segregation is maintained by air handling systems (as is often the case), then there must be control systems available to demonstrate that the systems are working properly.

The surfaces of the weighing area need to be of appropriate quality. They will have rounded corners and coving and be made of smooth impervious materials to enable easy cleaning. This standard of finish applies to the floor and ceiling as well as the walls. Since the changes of product are much more frequent in this area, the ability to clean is essential.

The cleaning methods used will need to be validated for effectiveness. This means that for each material there should be a SOP of the cleaning method to be used. The SOP should also specify the cleaning materials to be used. There should be logbooks.

Since the area is working with many different materials, it is potentially the area with the greatest possibility for a mix-up or cross-contamination. Provision of space for intermediate storage, order collection and order storage should be done whilst maintaining ease of movement and separation between orders.