Drug discovery differences between

From an industrial perspective, quantitative knowledge of the existence of different transporters within the cellular system used in screening procedures is of major importance as it can influence both the predictive value of the permeability coefficients and interpretation of the results. In addition, information on species differences or similarities or discrepancies between cell culture models and animals now provide an important basis for the scaling of data during the early phases of drug discovery for animals or humans [48]. 

The potential of photoprobes is increasingly utilized as a remotely controllable tool in the drug discovery process. The difference between the dark state stability and light sensitivity allows the separation of two actions ... 

Different formulation principles, dosage forms, and DDSs are commonly evaluated in animal models, and attempts are made to predict human absorption on the basis of such studies.80 Human studies are also conducted in some cases to confirm predictions from animal models. Chiou et a 1.81,82 demonstrated that there is a highly significant correlation of absorption (r2 = 0.97) between humans and rats with a slope near unity. In comparison, the correlation of absorption between dog and human was poor (r2 = 0.512) as compared to that between rat and human (r2 = 0.97). Therefore, although dog has been commonly employed as an animal model for studying oral absorption in drug discovery and development, one may need to exercise caution in the interpretation of data obtained. 

The most obvious difference between a normal cell and a cancerous one is that control of cell division has been lost in the latter. Since cell division requires synthesis of DNA, the synthesis, structure, and function of DNA have been frequent targets for discovery of antitumor agents. One of the problems with this approach is that some perfectly normal cells in the human body also turn over rapidly, including the cells in the bone marrow that eventually lead to the blood cells and the cells that line the gut. It is not surprising that the dose-limiting toxicity of many cancer drugs is damage to the bone marrow or the gut. 

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