Improved method for the determination of pyrimethamine in poultry and rabbit feeding stuffs by gas - liquid chromatography

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 microg/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 microg/cm2) and SUL (19.14 microg/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.

Development of a method for the determination of pyrimethamine concentrations in feeds by ion-pairing high-performance liquid chromatography

An ion-pairing reversed-phase high-performance liquid chromatography (HPLC) method with diode array detection at 280 nm was developed to determine pyrimethamine concentrations in feed for laying hens. Pyrimethamine was extracted with a mixture of 5% isobutanol and 95% benzene, and the extract was cleaned up on an alumina column. The drug was eluted from an Intersil ODS-3V column (250 by 4.6 mm) with a mixture of 25% acetonitrile and 75% water (vol/vol) containing 0.01 M tetramethylammonium chloride as an ion-pairing agent and adjusted with acetic acid to pH 3.5. The flow rate was 1.0 ml/min. Mean recovery of pyrimethamine from supplemented feeds at concentrations of 2, 4, and 5 microg/g of feed were 100.5, 103.5, and 100.8%, respectively. Precision within a day ranged from 4.3 to 7.0% for the three concentrations, and day-to-day precision was 5.3% for feed supplemented at a concentration of 4 microg/g. No chromatographic interference was detected from other 2,4-diaminopyrimidine compounds or other major drugs used in poultry.

Détermination des médicaments dans les aliments

Determination of drugs in foods. In foods, drugs can come from different sources: animal therapeutics, zootechnical feed supplementation or human food additives. The possible consequences arising from the presence of drugs in food are considered. The quantitative determination of drugs in feeds or in human foods must fulfil various requirements, including specificity, sensitivity, accuracy and rapidity. Spectroscopic, electrochemical and chromatographic techniques are discussed. Some examples reported are ipronidazole, pyrimethamine, diethylstilboestrol, decoquinate and chloramphenicol. The need for quality assurance in analysis is also discussed.