Molecular property filters describing pharmacokinetics and drug binding.

Drug-target binding affinity and pharmacokinetics are equally important factors of drug design. Simple molecular properties such as molecular size have been used as pharmacokinetic and/or drug-likeness filters during chemical library design and also correlated with binding affinity. In the present study, current property filters are reviewed, a collection of their optimal values is provided, and a statistical framework is introduced allowing calibration of their selectivity and sensitivity for drugs. The role of ligand efficiency indices in drug design is also described. It is concluded that the usefulness of property filters of molecular size and lipophilicity is limited as predictors of general drug-likeness. However, they demonstrate increased performance in specific cases, e.g. in central nervous system diseases, emphasizing their future importance in specific, disease-focused library design instead of general drug-likeness filtering.

A new easy-to-prepare homogeneous continuous electrochromatographic bed for enantiomer recognition.

Completely homogeneous polyacrylamide-based gels were used for capillary electrochromatography (CEC) of drug enantiomers. Like continuous beds (also called continuous polymer rods, silica rods, monoliths) they do not require frits to support the bed because it is covalently linked to the capillary wall. A long lifetime is an important feature of the beds. The gel matrices can be prepared in any laboratory and for specific interactions they can be derivatized with appropriate ligands. The application range is, therefore, broad. For chiral electrochromatography, negatively and positively charged polyacrylamide gels copolymerized with 2-hydroxy-3-allyloxy-propyl-beta-cyclodextrin (allyl-beta-CD) were prepared. The latter monomer was synthesized from beta-CD and allylglycidyl ether by a very simple one-step procedure. Eight acidic, neutral and basic drug compounds were resolved into their enantiomers, most of them with baseline separation. Interestingly, the resolution is independent of the electroendosmotic velocity, i.e., rapid analyses will not give low resolution. Upon increasing this velocity, the plate height for the fast enantiomer did not change (or decreased slightly), whereas that for the slow enantiomer increased. Only the last term in the van Deemter equation contributed significantly to the total plate height. The composition of the gel was chosen such that the "pores" became large enough to guarantee a satisfactory electroendosmotic flow (EOF). This open gel structure explains why acetone diffused as in free solution, i.e., independently of the presence of the gel matrix. This finding also indicates that the separation of small molecules in polyacrylamide gels cannot be explained by "molecular-sieving", but rather by some type of adsorption ("aromatic adsorption"?).

Ulcerative enterocolitis in dogs induced by drugs.

An ulcerative enterocolitis was induced in dogs by two drugs; cinchophen given intravenously or indomethacin given orally. Ulcers were closely associated with Peyer's patches with either drug. Granulomata were occasionally seen in the mucosa and adjacent mesenteric nodes of dogs who received cinchophen. Transmural inflammation was seen only in some dogs who received indomethacin. A skip-like distribution of mucosal lesions was seen, induced by either drug and corresponding to the skip-like collections of lymphoid follicles. An explanation of the pathogenesis of these lesions is offered in the light of recent advances in the understanding of the immune response of gut-associated lymphoid tissue.