Case Study: Limited Sample for Isolation
A client unexpectedly observed an API degradant in its formulation after 18 months on long-term stability studies. It had such a limited amount of formulated material available for isolation work, however, that it was unlikely to obtain sufficient purified isolate to enable full characterization by NMR and MS (see Stability Sample). A 10 mcg partially purified sample was characterized by MS and proton NMR only. A forced degradation condition was identified and implemented on bulk API (see Forced Degradation), allowing for >2 mg of the degradant to be generated, purified, and thoroughly characterized (Forced Degradation Isolate). For cross-identification purposes, a perfect match of data was established between the trace material isolated and the material generated chemically (HPLC RT, proton NMR, MS and MS/MS patterns).