Analysis of pharmaceutical dosage forms for oxfendazole: II. Simultaneous liquid chromatographic determination of oxfendazole and trichlorfon in equine paste.

This research article discusses a method developed for the parallel detection of two drugs, oxfendazole and trichlorfon, in horse paste using reverse phase liquid chromatography.

Method Description

• The research describes a process that uses reverse phase liquid chromatography to determine the presence of oxfendazole and trichlorfon in equine paste simultaneously.
• The material is first extracted through sonication in methanol, a technique that uses sound waves to agitate particles in a sample.
• Insoluble excipients, the substances other than the active drug in a medication, are then removed via centrifugation, where the sample is spun rapidly to separate substances of different densities.
• An aliquot, or portion of the sample, is taken along with an internal standard and then diluted with a dilution solvent composed of water, acetonitrile and phosphoric acid in an 80:20:1 ratio.
• The samples are then filtered and injected onto a Partisil-5 ODS-3 column, with a mobile phase of acetonitrile and a pH 6.0 phosphate buffer in a ratio of 20:80. The mobile phase is the solvent that carries the mixture being separated through the column in the chromatographic process.

Evaluation of the Method

• The article addresses the method’s specificity. Specificity is a key criteria in method development, since it impacts the ability to differentiate and quantify the study’s substances when the sample might have similar properties to others. Here, an absorbance rationing technique is employed to establish the specificity of the method.
• Findings showed that the method has high recovery rates for both trichlorfon and oxfendazole, at 100.9% and 100.0%, respectively. This indicates that the method is reliable in accurately extracting and quantifying these substances from the equine paste.
• The study also looked at how the performance of this chromatographic method can be affected by variables such as the organic content of the mobile phase, pH, and buffer concentration.