Clarithromycin form I determined by synchrotron X-ray powder diffraction.
The structure of the metastable form I polymorph of the macrolide antibiotic clarithromycin, C(38)H(69)NO(13), was determined by a powder diffraction method using synchrotron radiation. The space group of form I is P2(1)2(1)2. The initial model was determined by a molecular replacement method using the structure of clarithromycin form 0 as a search model, and the final structure was obtained through Rietveld refinements. In the form I crystal structure, the clarithromycin molecules are aligned parallel along the a axis in a head-to-tail manner with intermolecular hydrogen bonds between the hydroxy O atoms. The dimethylamine groups of the clarithromycin molecule interdigitate between neighbouring head-to-tail clarithromycin alignments. The novel crystal packing found in form I provides a mechanism that describes the transformation of form 0 to form I.
Graduate School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
Shuji
S
Noguchi
Keiko
K
Miura
Sadahiro
S
Fujiki
Yasunori
Y
Iwao
Shigeru
S
Itai
D017291:Clarithromycin / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D033362:Powder Diffraction / Q000379:methods*; D017356:Synchrotrons; D014961:X-Ray Diffraction / Q000379:methods*
D017291:Clarithromycin