A validated HPLC method for determining residues of a dual active ingredient anti-malarial drug on manufacturing equipment surfaces

Analytical method validation, determining the recovery rate from the equipment surface and the stability of a potential contaminant are important steps of a cleaning validation process. A rapid, sensitive and reproducible reversed-phase high-performance liquid chromatographic method was developed for the determination of pyrimethamine (PYR) and sulfadoxine (SUL) in cleaning validation swab samples. The active compounds can be selectively quantified in a sample matrix containing detergent and swab material as low as 0.12 μg/ml. The swabbing procedure used on stainless steel coupons was validated and the stability of PYR and SUL in the swab samples was assessed. The calculated limit of contamination values for PYR (4.99 μg/cm2) and SUL (19.14 μg/cm2) were not exceeded during four consecutive equipment cleaning trials. This confirms that the desired level of cleanliness is achieved with the current cleaning procedures, which are consequently validated.