Degradation peaks

The formation of the major UV degradation peak at about 287 nm in the weathered PC appears to correlate well with the formation of the yellow color in the weathered sample. In Figure 8 the formation of both the peak at 287 nm and the yellow color have been assumed to be products of a first order reaction. This figure shows a plot of the log of the percentage of a scaling constant minus the yellowness index divided by the constant, versus a measurement of the exposure. In this case, the exposure is expressed as cal/cm2, obtained from ENC0N data. 

System suitability is part of method validation. Experience gained during method development will give insights to help determine the system suitability requirements of the final method. An example is the hydrolysis of acetylsalicylic acid to salicylic acid in acidic media. Separation of this degradation peak from the analyte could be one criterion for the system suitability of an acetylsalicylic acid assay. 

Critical separations in chromatography should be investigated at the appropriate level. Specificity can best be demonstrated by the resolution of two chromographic peaks that elute close to each other. In the potency assay, one of the peaks would be the analyte peak. Figure 2.4 illustrates the selectivity of a method to resolve known degradation peaks from the parent peak. Based on the... 

Specificity. For HPLC analysis, resolution of the drug substance from any potential excipient and system interference peaks should be demonstrated. For a UV-Vis analysis, the absorption of the placebo solution should not be significant. It is important to note that the dissolution test is not intended to be stability indicating and will not need to be able to separate degradation peaks from the analyte peak. 

Prepare placebo sample and determine if interfering placebo peaks are present. Purposefully degrade placebo and determine if interfering degradant peaks are present. 

A stability study for 0.05 mg tablets of Compound B was conducted to support use of the formulation in clinical trials. Purity data from the 6-week and 12-week samples showed several impurity peaks above the 0.05% LOQ of the method, which were not present in the initial samples. These degradant peaks were present at higher levels in... 

Figure 18.15 X-ray diffraction patterns of Ca-C sorbent before and after the pyrolysis (a) before degradation (peaks due to CaCOa) (b) after degradation (peaks due to CaCl2 nH20), n = 2, 4. (Reproduced with permission from the American Chemical Society)...

Phosphate buffer ezetimibe degradation peak was detected following the peak of ezetimibe and separated from ezetimibe peak... 

When long-term storage stability profiles become available, these profiles can be used to justify a reduction in the degradant peak set. The scientific rationale for this decision should be documented. 

Peak Tracking Utilize diode array and LC-MS technology to track degradation peaks across orthogonal methods during sample screening... 

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