| Benefits |
•It measures the concentrations (drug or endogenous molecules) at the site of action
•It measures the unbound, pharmacologically active concentrations of the drugs
•The samples are protein free and this usually allows the direct determination of the drugs from the collected samples by bioanalytical techniques
•Microdialysis can be used to obtain concentration-time profiles over a consecutive number of days, because there is no fluid loss during sampling
•The experiments can be performed not only in anesthetized but also in freely moving animals
•The number of animals can be kept to a low level contrary to traditional PK studies where every time point needs different animals
•Microdialysis not only offers the possibility of sampling from certain tissues but also of delivering drugs directly to the site of action (retrodialysis)
•In the case of delivery mode, the drug effects can be studied locally without the risk of systemic adverse events or confounding drug effects
•More than one compound can be measured simultaneously
•More than one tissue (or brain region) can be studied simultaneously
•High resolution concentration-time profiles can be obtained from distinct brain regions
|
| Limitations |
•The implantation of the microdialysis probe into the brain or other target tissue could cause tissue trauma or damage (semi-invasive technique)
•The probe insertion into the brain parenchyma can increase the BBB permeability for 1-2 days
•The size of the molecules to be determined is limited by the cut off value of the probe membrane
•Several molecules show non-specific binding to the microdialysis setup
•Calibration is necessary as the probe recovery does not reach 100 %
•This techniques measure a mean concentration over a time interval
•Highly sensitive analytical method is necessary, capable of dealing with small sample volumes
•Microdialysis techniques are highly sophisticated low throughput methods
•Special surgical skills are needed to set up the experiments
|
|
