Szentesi A, Gergely A, Horváth P, Hosztafi S, Szász Gy
Department of Pharmaceutical Chemistry, Semmelweis University, Högyes E. u. 9, 1092 Budapest, Hungary.
Anal Bioanal Chem. 2002 Oct;374(3):427-31. doi: 10.1007/s00216-002-1510-9. Epub 2002 Sep 6.
A negative Cotton effect is observed in the circular dichroism (CD) spectra of 6-oxo-morphinans in the wavelength range of n-pi* electron transitions. 6-oxo-Morphinans can be transformed into oxime derivatives with hydroxylamine and after oxime formation the CD spectra are significantly different. Oxime formation was monitored by CD and by HPLC. It was established that under the experimental conditions used oxime formation was complete within 90 min. The method suggested for the determination of 6-oxo-morphinans is based on the considerable differences between the ellipticities before and after the oxime formation. The ellipticity difference varies linearly with concentration in the range 2 x 10(-5)-5 x 10(-4) mol L(-1) for the three 6-oxo-morphinans examined (oxycodone, hydrocodone, and 14-hydroxycodeinone). For hydrocodone the dependence is also linear in a lower concentration range (5 x 10(-6)-10(-4) mol L(-1)). The new difference CD spectroscopic method can be applied to the selective determination of 6-oxo-morphinans in bulk and dosage forms.
在6-氧代吗啡喃的圆二色性（CD）光谱中，在n-π*电子跃迁的波长范围内观察到负Cotton效应。6-氧代吗啡喃可以用羟胺转化为肟衍生物，形成肟后CD光谱有显著差异。通过CD和HPLC监测肟的形成。结果表明，在所使用的实验条件下，肟的形成在90分钟内完成。所建议的测定6-氧代吗啡喃的方法基于形成肟前后椭圆率的显著差异。对于所研究的三种6-氧代吗啡喃（羟考酮、氢可酮和14-羟基可待因酮），椭圆率差异在2×10⁻⁵ - 5×10⁻⁴ mol L⁻¹范围内随浓度呈线性变化。对于氢可酮，在较低浓度范围（5×10⁻⁶ - 10⁻⁴ mol L⁻¹）内这种依赖性也是线性的。这种新的差示CD光谱法可用于批量和剂型中6-氧代吗啡喃的选择性测定。
