| 摘要 |
<p>1315484 Cephalexin GLAXO LABORATORIES Ltd 2 July 1970 [25 July 1969] 37491/69 Heading C2A Cephalexin [7# - (D - 2 - aminophenyl acetamido) - 3 - methylceph - 3- em - 4 - carboxylic acid] having theγ-crystalline form is prepared by treating the #-crystalline (normal) form of cephalexin with methanol to form a suspension in which the total amount of water is less than 2% (w/v.) and perferably agitating the slurry until impurities are taken up in the methanol phase and the residual solid is in theγ-crystalline form. Theγ-crystalline form has infra-red peaks at 3500, 3210, 1774, 1692, 1540, 1344, 1324, 1262, 750 and 696 cm.<SP>-1</SP> (Fig. 2) and X-ray diffraction data is provided. Pure cephalexin is obtained by contacting the gamma crystalline form with water or an aqueous solvent medium (e.g. water-water miscible ketone) and allowing the beta crystals to develop.</p> |
