glassware cleaning validation

how to determine the worst case for the glassware ?
what mathimatical tool is adviced ?

thanks in advance

Dear IkbellmaN,

please clarify: What is the glassware used for? Which are the contamination and cross-contamination risks?

Best regards


thx Alfred,
In fact it’s a quality control lab in a pharmaceutical industry and it’s my ending studies project, the glassware is used for analyzing final products(drugs), raw material… so i think that the risk of cross-contamination is highly possible.

The way I would approach this is to look at the various factors involved:

1 Glassware used. Is the glassware a simple item like a beaker/conical flask with no or few areas where contamination could accumulate and can be easily cleaned, or is it a sintered glass filter funnel where there are plenty of areas for contamination to accumulate and can be difficult to clean effectively. Are there nooks and crannies or narrow bore tubing (that includes small volumetric flasks and pipettes)

2 The materials being handled - are they easily soluble in the “usual solvents” used for washing up, e.g. water, IMS, ethanol etc, or do they need acid/alkali treatment to remove the residues. Does the material produce obvious residues or is it freely soluble when making up “test” solutions

3 How is the glassware washed? Obviously this will influence cleanliness. If it is a washing machine - is it a specialised lab glassware washer with spikes of the correct lengths for tubular items etc. Do you use a pipette washer etc.?

I would then perform a risk assessment assigning an arbitary value for each of the major cross contamination risks from above e.g. 1 to 5 for simplicty of glassware shape so that a 100ml beaker would be 1 (v simple) to 5 for a sintered glass funnel or small pipette.

The relative risk would then = “shape” risk x “materials” risk x “cleaning method” risk

The higher the number, the greater the risk of cross contamination. As for software to do this, all you would really need at most would be a spreadsheet. Is there any need for anything more complex? I believe that the simple approach is probably the best!

Dear IkbellmaN,

I agree with David in the approach for the cleaning validation. Regarding the worst case, I assume you need to know how to determine the potential contaminant of the glassware that poses the highest risk of contamination. In this case, I would evaluate the risk from the point of view of analytical interference and not from the point of view of risk for the patient. As a first approach I would classify the glassware by methodology (a measuring cylinder used for tapped density will not have a possibility of interference with a HPLC method) in order to rule out possibilities of interference, and for each methodology you may evaluate which pair of analytes in contact with shared glassware has the highest interference. Depending on the number of analytes, methodologies and glassware it may be a daunting task!

Best regards


Dear Friends

First of all i would like to thank you for your help, in these times i feell like my project is not progressing and i need every help possible.
i have some questoins:

  • is there a mathimatical method to determine the risks that davidj mentionned ?
  • can we say that the analyte which has the lowest detection limit is the worst case ? and if it is i think that it don’t has any relation with cleanliness :confused:

use the above link for establishing a limit this is for a pharma manufacturing facility for cleaning validation. hope this will give you a rough idea to establish your own control limits.
to my understanding and past experience it is good to analyse the lowest concentration of the ingredients that was in that glass ware. analyse the washings of the glass ware for the remains of the analyte identified before. i think you need to establish the Lowest limit of detection to prove the cleanliness / carry over.