Chemistry Reference
In-Depth Information
Derivative spectroscopy may be used in the assay of Ephedrine Elixir
BP, which is used as a decongestant. This preparation is an oral solution
containing 0.3% w/v of ephedrine hydrochloride in a suitably flavoured
vehicle. The elixir is pink in colour and the presence of the pink dye inter-
feres with the simple UV assay, but the preparation may be analysed as
follows.
A number of standard dilutions of pure ephedrine hydrochloride are
prepared and their D
2
spectra are measured. A calibration curve of D
2
peak
height vs concentration is drawn. The elixir is diluted and the D
2
spectrum
D
0
Wavelength
D
1
Wavelength
D
2
Wavelength
Figure 7.18
Higher-order spectra D
1
and D
2
.
