Establishing acceptable limits (5)
11.9 The three most commonly used criteria are:
Spiking studies should determine the concentration at which most active ingredients are visible. This criterion may not be suitable for highpotency, low-dosage drugs;
no more than 10 ppm of one product will appear in another product (basis for heavy metals in starting materials); and
no more than 0.1% of the normal therapeutic dose of one product will appear in the maximum daily dose of a subsequent product.