Serum concentration of carbamazepine: comparison of Herrmann's spectrophotometric method and a new GLC method for the determination of carbamazepine.

A specific direct gas chromatographic method to determine carbamazepine and, semiquantitatively, 10,11-epoxy carbamazepine in serum is described. The average recovery of carbamazepine is 98%, and the error on duplicate determination is +/- 4%. The method is compared with Herrmann's classic spectrophotometric method. In material of 103 patients the mean serum concentration of carbamazepine was 25.5 +/- 12.8 mumoles/1 with GLC and 23.0 +/- 12.6 mumoles/1 with spectrophotometry. The difference was highly significant. The blood sample volume is one-tenth of that needed in spectrophotometry.