Development and validation of capillary electrophoresis methods for pharmaceutical dissolution assays.

: The determination of active compounds in samples of dissolution tests of oral solid dosage forms based on the USP 23 methods was performed by capillary electrophoresis after the use of solid-phase extraction disks for the preconcentration of drugs. Enrichment factors of 20:1 allowed the determination of betamethasone and ergotamine tartrate at levels of 0.33 microgram/mL and 1.0 microgram/mL, respectively. CE analysis was performed using fused-silica capillaries (35 or 60 cm length x 75 microns i.d.) and the operating conditions consisted of 15 kV applied voltage and UV detection at 254 nm. The background electrolyte was 20-mM phosphate borate buffer, pH 9.0, containing 50 mM of sodium cholate for the separation of betamethasone and 25 mM phosphate buffer, pH 3.0, for ergotamine tartrate. Validation of the methods was also performed. Accuracy and precision of the intraday and interday assays showed comparable results with those obtained by HPLC.