The kappa-active oxygen in the opioid pharmacophore of some benzomorphans: charges, proton affinities and binding modelling

Assessment of the kappa-opioid activity of a series of 6,7-benzomorphans in the rabbit vas deferens

The purpose of this study was to re-assess the classification in vivo of a series of (-)-normetazocine derivatives as kappa-opioid agonists. From their ability to inhibit contractions of the electrically stimulated rabbit vas deferens, the (2"S)-N-(2"-methoxypropyl) and N-(2"-methoxyisobutyl) derivatives were identified as full agonists. Several partial agonists were discerned, including the (2"S)-N-tetrahydrofurfuryl derivative, Mr2034. (+)-tifluadom, (+/-)-bremazocine, (-)-ketazocine and (+/-)-U-50,488 were used as reference compounds. Structure-activity relationships are discussed.

Applications of X-ray diffractometric techniques in the analysis of drugs

The principles underlying the diffraction of X-rays by crystals and the strategy of determining crystal structure are discussed; special attention is given to results obtained by X-ray crystallography. Examples illustrate how detailed study of the topographical characteristics of drug molecules of a particular pharmacological class may furnish a set of structural parameters that are helpful in understanding a given pharmacological response.