Pregna-1,4-diene-3,20-dione, 21,21'-(methylenebis((2-methoxy-1,3-naphthalenediyl)carbonyloxy))bis(9-fluoro-11-hydroxy-16,17-((1-methylethylidene)bis(oxy))-, (11beta,16alpha)-(11'beta,16'alpha)-, mixt. with urea