DETERMINATION OF VALPROIC ACID IN TEAR BY GCQ -ASSESSEMENT OF THE CONCENTRATIONS OF DRUGS ACTING ON THE CENTRAL NERVOUS SYSTEM IN TEAR-

The concentrations of sodium valproate (VPA) in tear and plasma by a quadrapole ion trap type GC/MS (GCQ) in a negative ion/chemical ionization/electroncapture mode. VPA was converted into the pentafluorobenzyl ester and was quantified by monitoring the ion of m/z 143. The VPA concentrations [C]Ts in the tear obtained from patients by non-invasive Schirmer method correlated very well with those of the unbound form in the plasma, indicating that the [C]TS will be used as a convenient index for monitoring the unbound VPA level in the patients.