Cleaning Validation

can we use 'single hardest to clean product " methodology for cleaning validation.
what are the justification require for it. we are considering the hardest to clean product on basis of following reason
*Insoluble in water or suitable solvent among all the products.
** Minimum daily therapeutic dose among all the products.
***Minimum batch size among all the products.
**** Maximum daily dose among all the products.
***** Second minimum daily dose among all products

Yes, you can. This is so-called “worst-case” approach which is commonly adopted in industry.
In addition to the justification for worst-case product selection, please consider toxicity of product and production frequency too. If the toxicity value of product is high and it is regular produced product, you should select the product in cleaning validation.

It can be done and is an effective tool, but I caution you to not do this without a thorough scintific understanding of the soils you have in your process. Do not try to just evaluate the solubility of each API and use that. Really understand all of the ingredients of the process and what it takes to clean everything. The worst case really only works when you area able to clean with the same process and can demonstrate that everything is removed. Please use caution with this as you may be able to show this with the API, but if you have something like a menthol excipient, you could still have menthol in the next product and get complaints of that in something that is not supposed to have it in it. Just make sure of what you are doing before you go into it.

what is the Emprical constant in Toxic criteria calculation