UREA INCLUSION COMPOUNDS OF n-ALKYL BROMIDES AND IODIDES

Abstract

The formation and stability of urea inclusion compounds of 71-all;)-1 bromides and iodides were established from X-ray powder diffraction data. T h e stabil~ty of both homologo~~s families is greater than would be expected from a consideration of the cross-sectio~lal diameter of the rnolec~~les only. 'The procedure for isolating the co~nplexcs has been simplified. INTRODUCTIOI\'

Urea inclusion compounds of enalapril maleate for the improvement of pharmaceutical characteristics

“…Diffractional peaks relevant to crystalline enalapril maleate were not detectable in EMIC products, indicating that the guest molecules were trapped and isolated from one another in the honeycomb network of urea and do not contribute to the crystal structure except for slight distortions of the hexagonal channels caused by bulky guests (Radell & Connolly 1961). The diffractogram of hexagonal urea (EMIC; important peaks at interplanar spacings at 4.16 (19%), 3.39 (100%) and 7.36 (5%) Å) (Radell & Connolly 1960;Brodman & Radell 1967) was characteristically distinguishable from that of the pure tetragonal form of urea (mainly characterized by the interplanar spacing at 4.04 (100%) Å) (Radell et al 1964), indicating a change in the crystalline form of urea.…”