Abstract
A quality control scheme for determination of antiepileptic drugs was conducted as the second attempt on a nationwide scale in June, 1978, in which 43 laboratories participated.
The freeze-dried control serum containing a series of known amounts of six drugs was usedfor the study.The drugs used were phenytoin, phenobarbital, primidone, carbamazepine, etho suximide and sodium valproate.The methods employed were GC (16 laboratories), EMIT (31), heterogeneous enzyme immunoassay (1), ultra violet method (3) and radioimmunoassay (1). Some of the participating laboratories performed more than two methods.
The mean values of each drug were found to be in good agreement with the spiked values, regar dless of the different levels of concentration and the methods used in this study.All the values of coefficient of variation (CV) fell in the range from 9.4 to 18.9%.There was no significant difference in CV between EMIT and GC. Most of the mean values by both methods agreed with the spiked concentrations.However, high level speci mens of phenobarbital and ethosuximide measu red by EMIT indicated a slightly higher levels than the spiked concentrations.
It is proposed that all laboratories that analyze antiepileptic drugs should check their procedures by themselves and participate in the quality control scheme which is to be regularly con tinued.
