Distribution of antiepileptic drugs between plasma, plasma water, cerebrospinal fluid, saliva and brain.

The following conclusions can be drawn from our results. The concentrations in cerebrospinal fluid correspond to the concentrations of the unbound part and saliva at a high lipid solubility. Cerebrospinal fluid and brain were interpreted as a uniform compartment. The unbound concentrations of low lipid soluble drugs in plasma do not reflect the concentrations of drugs in cerebrospinal fluid. The correlation between the unbound drug in plasma, CSF and brain must be determined. The concentrations of lipid soluble drugs in plasma, water or saliva is representative for the concentration of antiepileptic drugs in central nervous system.