Conformational polymorphism in bicalutamide
Related Experiment Video
Updated: Jul 20, 2026

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
Daniel R Vega1, Griselda Polla, Andrea Martinez
1Unidad de Actividad Física, Comisión Nacional de Energía Atómica, Avenida Gral. Paz 1499, 1650 San Martín, Buenos Aires, Argentina. vega@cnea.gov.ar
Abstract:
Two crystalline forms (forms I and II) and an amorphous phase of bicalutamide were fully characterized through combined results of differential scanning calorimetry, X-ray powder and single crystal diffraction and Raman spectroscopy. Each polymorph crystallizes with one molecule in the asymmetric unit and the molecular conformations are quite different between them. The main difference is provided by C12-C11-S8-C5 torsion angle, which assumes a value of -88.3(4) degrees (-Syn-Clinal) and 72.5(4) degrees (+Syn-Clinal) in forms I and II, respectively. Consequently, molecules in form I show an open folding and molecules in form II a closed one. The relative stability between forms I and II is presented in an energy versus temperature diagram, where forms I and II are considered as a monotropic system, being form I the more stable one. The amorphous phase was observed very metastable and it converts to form II spontaneously at RT in around a week.
More Related Videos
Related Concept Videos
Pharmaceutical Alternatives: Polymorphic Form-Related and Particle Size-Related Therapeutic Nonequivalence
Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
Stereoisomerism of Cyclic Compounds
Disubstituted Cyclohexanes: cis-trans Isomerism
In cyclohexane, the substituents can occupy different positions generating distinct isomers.

