Microdialysis technique illustration

Kreilgaard, 2001). The anesthetic effect of the two formulations indicated similar cutaneous absorption profiles of lidocaine from both formulations. Howcvct, a threefold increase in apparent absorption rate and a significant decrease in lag time of lidocaine applied in microemulsion vehicle compared to 5% xylocaine were demonstrated with cutaneous microdialysis. This study illustrated that, compared to the pharmacodynamic model, the microdialysis technique has higher sensitivity and less variability to access bioeqmvalence of topically applied chemicals. 

Figure 3. Illustration of the microdialysis technique, showing the hollow lumen of which a part consists of a semi-permeable membrane through which the analyte can enter the system.

The following section illustrates advances made using in vivo microdialysis by describing the contributions of this technique to the study of memory and drug addiction, which are our areas of research interest. In addition, we have chosen two areas that present unique challenges and new apphcations of this procedure, specifically the study of ontological development and the use of in vivo microdialysis in human research... 

Mass spectrometry is another detection technique widely used in neuropeptide analysis. Concentration sensitivities in CE-MS do not reach those obtained by CE-LIF nevertheless, tedious derivatization procedures are avoided. In addition, CE-MS has proven to be a powerful tool for structure elucidation as illustrated by the investigation of the in vivo metabolic fate of peptide E by Caprioli s group [12]. After microdialysis and in-line SPE, neuropeptides migrating out of the electrophoresis capillary were deposited directly onto a precoated cellulose target used in matrix-assisted laser desorption-time of flight (MALDI-TOF) MS subsequently. Structural information is then obtained along with the mass of the peptide(s). 

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