Metal detection maximum permissible rejected tablets

Hi all!

Do anybody have experience establishing a technical rationale for the maximum permissible number of rejected tablets at the end of a compression run? 

I have to answer an Audit observation on this regards and would appreciate all the help I can get.

You need to validate your process to reach a number that works for you...and since your making tablets, this will probably be a % of the days run(s)

Assuming your making 100s of 1000s units/day

I don't know that any would be "permissible" without figuring out where the metal is coming from?  

What exactly did the auditor say?

Scampi,

First thanks for your quick response.

Metal can comes from several sources including raw materials, closure systems, and the same manufacturing equipment.  Especially from those that have moving parts like mills and tablet press.  

My dilemma is that due to several factors (e.g.: metal check sensitivity, limited room space, vibration, etc.) a significant amount of cores (> 1% of 800 kg batch) are typically rejected during the compression process. 

Most of this material are false rejections.  It is a fact that at least a dozen of tablets are “rejected” everytime the diverting mechanism of the metal detector is activated.  Not all of them necessarily have metal.  I did a quick trial in one occasion where more than 15 kg (~10,000 cores) were collected as combined wastes from right and left sides metal detectors.  After the completion of the batch, the rejected tablets were slowly passed through the corresponding metal detector and about 20 tabs in total were rejected.  However, this is not our normal practice since our effective SOP only instructs the operator to document the amount of waste and discard it. 

From the quality point of view, the excessive amount of false rejected tablets eventually may mask a real metal content issue that could put at risk the patient health.  That is why the auditor is requesting that a limit is established, either by weight or number of tablets, to discriminate between what would be an acceptable amount of rejected tablets in a typical batch and what should rise a flag (investigation) to determine if a batch can be released for distribution if the limit is exceeded.

The actual observation was:

There is no limit defined for rejects in the metal detection during tablet compression. The rejects are not checked, but just discarded at the end of the compression of the batch. 

My intention is to define a technically sound limit that fit the purpose but at the same time do not create a problem due to excessive number of investigations due to false rejects.  I believe that for the last part the reprocessing at the end of the batch to differentiate the true and the false rejects can be a fix. 

Where I need more help is with the rational I must use to define the limit.

Probably insufficient data at moment.

Pharmaceutical ?

Offhand 1% rejection for metal sounds astronomic.

instrument sensitivity ?.

Current (average/variation?) percentage rate of rejection ? eg rejects per 100 tablets per day

True percentage rate of rejection ?

Hi, Charles!

Pharmaceutical ? Yes

instrument sensitivity ? Probably a combination of sensitivity, vibration and small room with very limited space for operators to move around during the process

Current (average/variation?) percentage rate of rejection ? eg rejects per 100 tablets per day Rough estimate of >1% per 800 kg batch.  One batch is done in 3 shifts.

True percentage rate of rejection ? Unknown

Going back to the basics. 

I am already dealing with the reduction / elimination of the excess rejects. 

• There is in place a major project to move the press to a bigger room. 
• The detector sensitivity has been adjusted by the mechanics as much as possible but ensuring that they still reject based on the challenges with the SS, NFE and FE standards.
• Operators have been instructed to avoid unnecessary transit close to the metal detectors.
• Vibration has been reduced as much as possible.

My posting main goal is to get help with the strategy to define the limit for the maximum amount of rejected tablets by the metal detector that will trigger investigations in case that the amount of cores (by count or weight) is exceeded.

Your help is really apprecaited!

Hi, Charles!

 

Pharmaceutical ? Yes

 

instrument sensitivity ? Probably a combination of sensitivity, vibration and small room with very limited space for operators to move around during the process

 

Current (average/variation?) percentage rate of rejection ? eg rejects per 100 tablets per day Rough estimate of >1% per 800 kg batch.  One batch is done in 3 shifts.

 

True percentage rate of rejection ? Unknown

 

Going back to the basics. 

 

I am already dealing with the reduction / elimination of the excess rejects. 

• There is in place a major project to move the press to a bigger room. 
• The detector sensitivity has been adjusted by the mechanics as much as possible but ensuring that they still reject based on the challenges with the SS, NFE and FE standards.
• Operators have been instructed to avoid unnecessary transit close to the metal detectors.
• Vibration has been reduced as much as possible.

My posting main goal is to get help with the strategy to define the limit for the maximum amount of rejected tablets by the metal detector that will trigger investigations in case that the amount of cores (by count or weight) is exceeded.

 

Your help is really apprecaited!

Hi orengoa,

Thks for response.

Obviously a major pharmaceutical problem.

By instrument  sensitivity I meant what is yr current  (millimetre) setting for ferrous, non-ferrous, stainless ?. (often a compromise between LOD and too many false rejections)

The "unknown" is unfortunately  the critical number ! :smile: