W0261
Analysis of Three Active Pharmaceutical Compounds Using
X-Ray Powder Diffraction Techniques. R. Toro(1), A.
Uzcátegui(1), C. Cedeño(1), E.
González(2), G. Díaz de Delgado(1), J.M.
Delgado(1). (1)Laboratorio de Cristalografía-LNDRX,
Depto. de Química, Fac. de Ciencias and (2)PROULA, Universidad
de Los Andes, Mérida, Venezuela.
Solid state properties, such as crystallinity, thermal and
hygroscopical behaviour, as well as the tendency to exhibit polymorphism under
varying crystallization conditions, are of special interest in the
characterization of pharmaceutical compounds. The structural characterization of
atenolol (C14H22N2O3), meloxicam
(C14H13N3O4S2) and
enalapril maleate
(C20H28N2O5·C4H4O4)
have been carried out using X-ray powder diffraction techniques. The X-ray
patterns were recorded using a Philips PW1250 goniometer automated by Crystal
Logic, Inc., with CuKα radiation, in the range of 2-50º (2θ),
step of 0.02∞ and 10 seconds. They were processed and analyzed with the
package JADE 5.0 (MDI) after being recorded on specimens prepared (a) as
commercially obtained, (b) after recrystallization (the solvent systems
investigated included water, acetone, methanol, ethanol, ethyl acetate,
acetonitrile, and dioxane). The analysis of the diffraction patterns collected
for the different specimens indicated the presence of several polymorphs. For
example, the commercial sample of atenolol (a white solid with melting point of
152ºC) exhibits a monoclinic system with unit cell parameters
a=27.65(1) Å, b=4.887(3)Å, c=5.625(6)Å,
β=95.73(6)º, V=756.43 Å3. After crystallization by
controlled evaporation of the solvent (ethanol and methanol), it crystallizes as
brilliant white plates with melting point of 147º and 148ºC
respectively. Both exhibit an orthorhombic unit cell with
a=27.43(9)Å, b=5.489(3)Å, c=5.012(1)º
Å, V=754.8 Å3 (ethanol). Crystallization of atenolol by
vapor diffusion of ether using ethanol as solvent, produces a light yellow solid
with melting point of 107ºC with a monoclinic unit cell. Details of the
analysis and the results obtained for the three compounds under study will be
presented in this contribution.
This work has been possible through grant LAB-97000821 from
FONACIT.