A rapid LC method for the identification and determination of CNS drugs in pharmaceutical formulations.
Antidepressant, neuroleptic and antiepileptic drugs were identified and determined in pharmaceutical formulations (tablets, capsules and oral solutions) by a rapid high-performance liquid chromatography method. The sample pretreatment consisted of a one-step extraction, filtration and dilution. The chromatographic conditions were: reversed-phase C8 column (150 x 4.6 mm i.d., 5 microm); acetonitrile-tetramethylammonium perchlorate aqueous solution (pH 2.8; 12.6 mM) (45:55, v/v) as the mobile phase; detection wavelength, 230 nm. Calibration curves were linear in the 100-1000 ng ml(-1) range for all tested drugs except for phenobarbital. The repeatability (or intra-day precision), expressed by the relative standard deviation, was better than 2.0%. The accuracy, resulting from recovery studies, was between 98.1 and 101.3%. The amount of drug found agreed with the declared content within the limits specified by United States Pharmacopeia and British Pharmacopeia.