Similar to the characterization of decomposition products,
preparative HPLC separation followed by detailed NMR and MS
spectroscopic investigation enabled the structural characterization
of low level process related impurities of vinorelbine bitartarate
and ALB (C(10)-SCH3 analogue of VLB (Fig. 1), under phase I clinical
trial) [51] and of VLB and VCR impurities. In the case of ALB impurities,
the sensitivity of the available NMR microprobe enabled
these characterizations from a few mg of collected samples. In
the case of the novel VLB and VCR trace impurities, the utilization
of our 800 MHz NMR spectrometer equipped with a cryoprobe
complemented with detailed fragmentation information derived
from high-resolution MS–MS measurements enabled the characterization
of the unknowns from a few mg of impurity-enriched
samples [43].