Comparison of OPLC and other chromatographic methods (TLC, HPLC, and GC) for in-process purity testing of nandrolone

A semiquantitative OPLC purity test has been developed for in-process control of nandrolone and compared with other chromatographic methods. TLC was not sufficiently selective, a key impurity with low UV absorption could not be detected by HPLC, and nandrolone was slightly degraded during gas chromatography. OPLC proved to be a suitable means of testing for all potential impurities in nandrolone. The separation was performed by multiple development on fine-particle silica gel with cyclohexane-ethyl acetate-chloroform, 50 + 25 + 25 (nu/nu), as mobile phase. After spraying the chromatograms with sulfuric acid, then heating, the impurities could be sensitively detected by visual inspection in long-wave UV light. Detection limits were less than or equal to0.01 mug.