Minimizing the risk of cross contamination in a pharmaceutical central chemicals dispensing room

In a non pen non sterile pharmaceutical production facility (producing many pharmaceutical products) in which there is a central chemicals dispensing room

The central chemicals dispensing room has the following characteristics:

1- The dispensing room has a LAF weighing booth in which preparation chemicals are manually weighed using scoop and balance

2- Certain amounts of preparation chemicals are weighed from the raw materials containers to obtain a cage containing certain amounts of chemicals (active & inactive) to be dispensed for the preparation of a certain batch of a certain pharmaceutical product

3- The rest of the chemical remaining in the original raw material container after weighing (e.g. inactive ingredients e.g. diluents such as starch) can be weighed and dispensed in the future for the preparation of a batch of another pharmaceutical product, i.e. the inactive ingredient is common for more than one product

I believe that after weighing the API of a certain product, certain measures should be conducted before weighing an inactive ingredient of the same product (but this inactive ingredient is common for more than one product) such as:

1- the whole weighing booth and the balance should be wet cleaned

2- the scoop used for weighing the API should be cleared from the area

3- secondary gowning of the weighing person should be changed

These measures should be conducted to minimize the risk of contaminating the original raw material container of this inactive ingredient with traces of the previously weighed API, because if it is contaminated this contamination may be introduced in the future into another pharmaceutical product since the rest of this inactive chemical remaining in the original raw material container (e.g. diluents such as starch) can be weighed and dispensed in the future for the preparation of a batch of another pharmaceutical product

Am I right ?

Another question:

If the production department demands that chemicals for 5 batches of a certain product are weighed,
Call no.s of batches (1,2,3,4,5) and call the names of chemicals (A, B, C, D)

I believe that the best approach to minimize the risk of cross contamination into original raw materials containers should include some procedures such as:

1- Not to weigh the chemicals for batch no. 1 then weigh the chemicals for batch no. 2 and so on , but the right approach is to weigh the 5 amounts of chemical A for the 5 Batches consecutively then weigh the 5 amounts of chemical B for the 5 Batches consecutively and so on

2- Chemicals are weighed in ascending order of chemical risk, i.e. first inactive ingredients are weighed e.g. diluents followed by weighing colorants & flavors if present , and finally API is weighed

3- Weighing booth clearance & dry cleaning and convenient time interval should be present between each inactive chemical and the following chemical

4- After weighing the API, the previous step is performed in addition to wet cleaning, even if other batches of the same product are required to be weighed after weighing this API, as previously illustrated

Am I right ?

Thanks a lot

This approach will require the presence of 5 cages for 5 batches of the same product in which chemicals for each batch are distributed, i.e multiple Batches of the same product are present concomitantly in the same dispensing room,

I think that further measures will be required to ensure absence of mix up between these batches of this product, so that the measures conducted to minimize cross-contamination do not lead to high risk of mix-up

the further measures could be:
1- SOP instructions for operators that should be followed strictly to avoid occurrence of mix-up,
Examples of these SOP instructions are
A- to put movable partitions between each cage (pallet) and the adjacent one of another Batch and putting a large ID Label containing Batch No. at each one
B- If there are modified Batches of the same product (of modified Batch size) the chemicals of these batches are weighed in a separate campaign , not with ordinary unmodified Batches

2- Continuous triple check on the application of these instructions and on the absence of mix-up during dispensing process, by dispensing room supervisor and QA personnel.

@Awad you are right and the said procedure can be applied after implementation of satisfactory measures to avoid the mix-up of the materials.

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