Three previously unreported manufacturing impurities were isolated from a p
holcodine mother liquor using preparative reversed-phase HPLC.
The liquor was the residue remaining after recrystallisation of a productio
n batch of pholcodine. The impurities, which are structurally related to ph
olcodine, were initially detected by thin-layer chromatography (TLC). Their
structures were determined after separation by preparative HPLC (Econo-Pre
p 5 mu m C18 column, 30cm x 21.2 mm i.d.). Structure elucidation was carrie
d out using nuclear magnetic resonance (NMR) spectroscopy, mass spectroscop
y (MS) and ultra violet (UV) spectroscopy.
The impurities were identified as alkylated derivatives of pholcodine posse
ssing second 2-morpholinoethyl substituents at various positions.