Calculating, dopamine dose

There are three steps necessary to calculate the proper dose of dopamine to administer to the patient. These are ... 

Using microdialysis experiments the relative oral bioavailabilities of the compounds 34, 35 and 5-OH-DPAT could be calculated.215 The relative oral bioavailabilities were calculated by comparing the Areas Under the Curve (AUCs) after oral and subcutaneous administration. When there was no significant difference between the AUCs the subcutaneous dose was divided by the oral dose and multiplied by 100 to give the relative oral bioavailability. These data show that, although the affinities of the benzo[ ]thiophenes (34 and 35) for the dopamine receptors are lower as compared to 5-OH-DPAT, the relative oral bioavailability is higher. Therefore, the benzo[/i]thiophenes are interesting compounds for further research. 

The relative oral bioavailabilities, as determined by comparing the AUC after s.c. and p.o. administration, of 6-(N,N-di- -propylamino)tetrahydrobenzo[/>]thiophene (34), 5-(N,N-di- -propylamino)tetrahydrobenzo[/>]thiophene (35) and 5-OH-DPAT (9) were calculated from Figures 4.1-4.3, and are shown in Table 4.2. For compounds 34 and 35 the relative oral bioavailabilities were > 10 %, while for the reference compound 5-OH-DPAT it was 1 %. In order to verify the fact that the decrease induced by a dose of 10 pmol/kg p.o. was not already induced by a lower dose, we have found that a dose of 1 pmol/kg p.o. of 5-OH-DPAT induced a decrease in the release of dopamine in the striatum of only 50-55 %. Furthermore, microdialysis experiments in our laboratory with the (-)-enantiomer of 5-OH-DPAT also showed that the relative oral bioavailability was about 1-3 % (Chapter 7). 

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