X-RAY ABSOLUTE STRUCTURE OF NICERGOLINE (FORM-I) - QUANTITATIVE-ANALYSIS OF NICERGOLINE PHASE MIXTURE - FORM-I FORM-II

The structure of semisynthetic ergot derivative nicergoline (form I) was determined from X-ray single crystal diffraction data. The tide alkaloid (10alpha-methoxy-1,6-dimethylergoline-8beta-methanol-5'-bromonicotinate, C24H26BrN3O3) crystallizes in the triclinic space group P1, with a = 7.729(7), b = 8.695(4), c = 17.030(8) angstrom, alpha = 100.90(4), beta = 98.67(5), gamma = 93.04(5)-degrees, Z = 2. A structural comparison of nicergoline forms I and II was made. The quantitative analyses of some model phase mixtures form I/form II were carried out using both Rietveld full profile fitting method and linear regression of the peak intensity-concentration dependence. Results obtained are in good mutual agreement. The smallest limit of detection of form II in binary mixture with form I is about 3% as found from powder diffraction study.