Pseudomorphic Crystal Growth of the Model Steroid Methyl Analogue of Norethindrone

Abstract

Various morphologies of two polymorphs of a steroid are observed and correlated to calculated morphologies using the connected net theory. In a previous publication on our model compound, we reported polymorphic epitaxial growth as a result of variations in the supersaturation. Two additional and also unusual types of growth behavior are described in this work: the observation of crystals that have a morphology that does not correspond to its observed polymorph, also called pseudomorphism, and the observation of a particular crystal face on which distinctive faceted pits occurred. The particular kinetic growth behavior of this model compound is explained by the fact that the two polymorphs are partly isostructural and by impurity induced growth hampering.

Crystal structure of isotibolone: a major degradation product of tibolone

“…1a) rings revealed that atoms C(11), C(9), C(16) and C(15) are, respectively, the most deviating ones from perfect planar rings. The highest deviations from the leastsquares plane passing through those rings are 0.309 (4) A for C(11), À0.256 (3) A for C(9), 0.255(3) A for C(16) and À0.314(2) A for C (15). The root mean square errors (rmse) of contributing atoms, for each ring displayed in Fig.…”

“…1a). 4 The isomer is formed when tibolone is exposed to high temperatures and/or acidic conditions. The potential for significant degradation of tibolone to isotibolone makes it difficult to formulate and provide a pharmaceutical composition with acceptable life-time storage for a marketed product.…”

Interlaced spiral growth and step splitting on a steroid crystal

“…We only consider PBCs that are restricted to the observed slice thickness d 040 . Using the crystal graph (network of bonds) and bond energies determined by Boerrigter et al [39], we come to four PBC directions for each layer X and Y: Interesting is the fact that, although the [1 0 1] steps are the fastest propagating ones, they are always straight. This indicates that the kink density is lower, i.e.…”

Quantifying Isotibolone in Raw Materials of Tibolone

“…The isomer is formed at high-temperature exposure and/or acidic conditions. The isomerization mechanism involves the rearrangement on the A-ring of the double bound from carbon atoms 5 -10 to 4 -5 [3].…”