The principles of the 3Rs, Replacement, Reduction and Refinement, are being increasingly incorporated into legislations, guidelines and practice of animal experiments in order to safeguard animal welfare. In the present study we have studied the systematic application of 3R principles to toxicological research in the pharmaceutical industry, with particular focus on achieving reductions in animal numbers used in regulatory and investigatory in vivo studies. The work also details major factors influencing these reductions including the conception of ideas, cross-departmental working and acceptance into the work process. Data from 36 reduction projects were collected retrospectively from work between 2006 and 2010. Substantial reduction in animal use was achieved by different strategies, including improved study design, method development and project coordination. Major animal savings were shown in both regulatory and investigative safety studies. If a similar (i.e. 53%) reduction had been achieved simultaneously within the twelve largest pharmaceutical companies, the equivalent reduction world-wide would be about 150,000 rats annually. The results point at the importance of a strong 3R culture, with scientific engagement, collaboration and a responsive management being vital components. A strong commitment in leadership for the 3R is recommended to be translated into cross-department and inter-profession involvement in projects for innovation, validation and implementation. Synergies between all the three Rs are observed and conclude that in silico-, in vitro- and in vivo-methods all hold the potential for applying the reduction R and should be consequently coordinated at a strategic level.

Drug toxicity observed in animal studies during drug development accounts for the discontinuation of many drug candidates, with the kidney being a major site of tissue damage. Extensive investigations are often required to reveal the mechanisms underlying such toxicological events and in the case of crystalline deposits the chemical composition can be problematic to determine. In the present study, we have used mass spectrometry imaging combined with a set of advanced analytical techniques to characterize such crystalline deposits in situ. Two potential microsomal prostaglandin E synthase 1 inhibitors, with similar chemical structure, were administered to rats over a seven day period. This resulted in kidney damage with marked tubular degeneration/regeneration and crystal deposits within the tissue that was detected by histopathology. Results from direct tissue section analysis by matrix-assisted laser desorption ionization mass spectrometry imaging were combined with data obtained following manual crystal dissection analyzed by liquid chromatography mass spectrometry and nuclear magnetic resonance spectroscopy. The chemical composition of the crystal deposits was successfully identified as a common metabolite, bisulphonamide, of the two drug candidates. In addition, an un-targeted analysis revealed molecular changes in the kidney that were specifically associated with the area of the tissue defined as pathologically damaged. In the presented study, we show the usefulness of combining mass spectrometry imaging with an array of powerful analytical tools to solve complex toxicological problems occurring during drug development.

Ketoconazole consistently affected the disposition of venlafaxine in EMs of debrisoquine while the response in PMs was erratic. The precise mechanisms underlying this interaction remain to be elucidated.

Owing to their naturally aggressive behaviour, male mice are often housed individually in toxicity studies. However, several publications advocate group-housing of mice to enable normal social behaviour and interactions between the animals. This refinement project aimed at facilitate group-housing in toxicity studies. A handling procedure, including key factors such as allocation into groups before sexual maturation, transfer of used nesting material into clean cages and avoidance of external changes, that makes group-housing of male CD-1 mice possible in long-term toxicity studies has been developed at Safety Assessment within AstraZeneca, Sweden. Observations on the effect on aggression/fighting in group-housed male mice following different procedures performed in toxicity studies have shown that temporary removal of animals from the group for blood or urine sampling does not affect the group dynamics. However, temporary removal of animals for mating leads to fighting if the animals are taken back to the original group. Treatment with test compound might affect the general condition of the animals and the social hierarchy could be changed. In such cases aggression/fighting might occur and the animals have to be separated. Our experience clearly indicates that group housing of male mice in long-term studies leads to more easily handled animals, as compared with individually housed mice.