Determination of anticonvulsants in serum

The above mentioned anticonvulsants can be analysed solely or combined by this procedure. It is demonstrated by primidone as follows.
Primidone is used in therapy for control of complex partial psychomotor seizures. It is rapidly metabolized to phenobarbital and 2-ethyl-2-phenylmalonamide (PEMA). Patients are usually monitored for both phenobarbital and primidone serum levels. Previous studies have reported coefficients of variation for primidone as high as ± 25% when analysed by HPLC and GC. This could be due to the UV absorbance characteristics and polarity of the compound. The precision of the HPTLC method presented here is about ± 2% for primidone, phenobarbital and PEMA in serum.
The anticonvulsants are extracted with dichloromethane – isopropanol and then concentrated. The residue is taken up in dichlormethanol – methanol and separated on silica gel. It is quantitatively determined by absorbance measurement at 215 nm.