Stanek. Different strength from one batch to the next


About a week ago I started a new bottle of Stanek and it has just dawned on me that I have not needed to top up my dose with a Sinemet Plus pill in the middle of the night and that my Off periods during the day have not been so long.  While I was taking the last batch, my symptoms were pretty bad, my wife thought so as well.

I suspect quality control is poor,


Batch-to-batch variability is an important topic for PwP. We are likely to notice even a 10% change of concentration. I was hoping to find what batch-to-batch variations were deemed acceptable by the regulators, but couldn't.

There is more information on the criteria for acceptance of generic drugs

The Wikipedia article on bioequivalence is a good starting point. Bioequivalence is usually based on pharmacokinetic properties such as CMAX, maximum concentration, and AUC, area under the curve. It says that the 90% confidence interval of the measurements of the ratios  between the original and the generic must be within 80% and 125%. Please note that the mathematical nuances of this statement mean that this is not the same as saying that a 20% reduction in potency would be acceptable. (For instance, if the mean was 80%, about 50% of the samples would be below 80%, and therefore breaking the 90% CI rule.) I'd estimate that a 10% difference would be possible.

Just out of interest, it would not be conclusive, just indicative, but has anyone got a scale accurate enough to weigh a pill?




I have a little set of scales that wil go down to 0.001 of a gram.  Out of 6 or so tablets I weighed, the lightest is 0.792 grams and the heaviest is  0.838 grams.  I did not realise there could be so much variation.


Hi Martini,

We would suggest flagging a Yellow Card for defective medication with the MHRA at

The MHRA monitor the safety of all healthcare products in the UK to ensure they are acceptably safe for those that use them. The Yellow Card Scheme allows issues to be identified and the appropriate action to be taken.

I hope you find the above information useful.

Many thanks,