Target-dose approach

There seems little doubt that the target dose approach has much potential, offering considerable advantages over previous methods for estimating toxicological risks particularly... 

Currently, human risk assessment utilising the target dose approach must be based on quantitative dose-response data generated in one or more presumed-sensitive biological models. The risk estimates developed using this approach must be carefully checked against the results of current and future human epidemiological studies. 

Applications of the Target Dose Approach in Pesticide Toxicology... 

The relationship between dose and effect can be separated into pharmacokinetic (dose-concentration) and pharmacodynamic (concentration-effect) components. Concentration provides the link between pharmacokinetics and pharmacodynamics and is the focus of the target concentration approach to rational dosing. The three primary processes of pharmacokinetics are absorption, distribution, and elimination. 

In conclusion, the immunological system was a sensitive target of CDD toxicity under experimental conditions in animals. Effects on all types of mediated immunity were seen at doses of 2,3,7,8-TCDD as low as 0.01 g/kg. Doses of 2,3,7,8-TCDD that were well below the lethal dose affect humoral immunity. Thymic atrophy occurs as single or multiple doses approach those that may increase lethality. Neonates and young animals are much more sensitive than adults to most of the immunological responses. 

A concern with AUC-targeting based on renal function surrounds the measurement of creatinine clearance. The formulas of Calvert et al. were developed using EDTA clearance, measurement of which is not widely available. They have shown that neither standard measured creatinine clearance, nor the calculation of this index are as accurate or as reproducible. To circumvent this difficulty an alternative dosing strategy has been developed by Chatelut, Canal and co-workers [226], This dosing approach is being tested in clinical trials. 

Other refinements could be provided by implementing the target-organ toxicity dose approach, which attempts to estimate the plausible critical effect and IOC that would have been calculated had the particular mixture been tested (Mumtaz et al. 1994, 1997). This approach is complicated, and would be suggested only when additional assessment is needed, perhaps to resolve differences between expected and actual health effects outcomes, or where critical effects are different across constituents or fractions that make up the mixture. ... 

The physical state of a pollutant is obviously important a particulate coUector cannot remove vapor. Pollutant concentration and carrier gas quantity ate necessary to estimate coUector si2e and requited efficiency and knowledge of a poUutant s chemistry may suggest alternative approaches to treatment. Emission standards may set coUection efficiency, but specific regulations do not exist for many trace emissions. In such cases emission targets must be set by dose—exposure time relationships obtained from effects on vegetation, animals, and humans. With such information, a Ust of possible treatment methods can be made (see Table 1). 

Polymeric microparticles have been studied and developed for several years. Their contribution in the pharmacy field is of utmost importance in order to improve the efficiency of oral delivery of drugs. As drug carriers, polymer-based microparticles may avoid the early degradation of active molecules in undesirable sites of the gastrointestinal tract, mask unpleasant taste of drugs, reduce doses and side effects and improve bioavailability. Also, they allow the production of site-specific drug targeting, which consists of a suitable approach for the delivery of active molecules into desired tissues or cells in order to increase their efficiency. 

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