Solid state interaction of steroids with calixarenes. I. A preliminary FTIR and DSC study on 4-en-3-keto-steroids

Both DSC and FTIR studies indicate that co-grinding and co-precipitation cause steroids to interact with calixarenes. This interaction leads to breaking of the crystal lattice of the steroids, dispersion of the steroidal carbonyls in a hydrophobic environment and formation of hydrogen bonds between steroidal and calixarene hydroxyls. This interaction seems to be specific, depending on the structure of the calixarene and of the steroid involved. It is reasonable to assume that inclusion complexes are formed.