Impurities Resulting from the Synthesis Pathway

As can be concluded from the examples described above, further applications of NMR spectroscopy can be expected to be introduced to the Ph. Eur. and national European pharmacopoeias as well as the JP and the USP in the future. The high potential of NMR spectroscopy in terms of identification and quantification of drugs and their impurities resulting from the synthesis pathway or degradation will be demonstrated in the following sections. 

Identification and Quantification of Impurities in Drugs Impurities Resulting from the Synthesis Pathway 

Compound Old commercial sample [18] Synthesis sample Sample provided by Ravensberg 

the new samples meet the demand of the content described as not less than 95.0% and not more than the equivalent of 101.0% in the DAB 1998 and Pharmeuropa [21]. 

Vitamin E, a-tocopherol as free phenol, acetate or succinate ester, contains small amounts of P-, y-, and/or 5-tocopherol. Owing to the sometimes poor resolution and the requirement for an authentic reference standard, HPLC and GC analysis turned out to be unsatisfactory. Baker and Myers [25] could prove that both methods, h and NMR, arc suitable to quantify the composition of vitamin E by integration of corresponding signals. 

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