Determination of Oxyclozanide in Beef and Milk using High-Performance Liquid Chromatography System with UV Detector

Development and Validation of RP-HPLC Method for the Simultaneous Determination of Levamisole HCl and Oxyclozanide and its Application in the Assay of Veterinary Bolus Formulations

Introduction:

A reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous analysis of two drugs, levamisole hydrochloride (LH) and oxyclozanide (OX), in co-formulation for veterinary use.

Materials and Methods:

The new HPLC method was validated as per the ICH and other guidelines. A C18 column was used with a gradient program; eluent A was an equal mixture of methanol and acetonitrile, and eluent B included a 25 mM phosphate buffer at pH 7.0 containing 30 mM sodium decanesulfonate and triethylamine (50:50:1 v/v) with pH adjusted to 7.0 using H3PO4 [51:49 v/v] .The detection wavelength was set at 220 nm. For the final gradient program, the retention times were 8.2(for LH) and 13.6(for OX) minutes, respectively, at a flow rate of 1 ml/min over 20 minutes run time.

Results:

The method was precise, specific and robust. The correlation coefficient, R2 was 0.9998 and 0.9999 for LH and OX, respectively in the range of 5 – 280 μg / mL. The percent y-intercepts and percent residual standard deviations were 1.6%/0.4% and 1.4%/1.0% for LH and OX, respectively. The LOD and LOQ of the method were 0.21 μg / mL and 0.62 μg / mL for LH and 0.06 μg / mL and 0.18 μg / mL for OX. The method has an average accuracy of 100.5% for LH and 101.1% for OX when tested on veterinary bolus formulations, and the samples could be stored under typical lab conditions for about 7 days without significant degradation.

Conclusion:

This HPLC method is suitable for assaying levamisole hydrochloride and oxyclozanide simultaneously from veterinary formulations.

Development of a New Analytical Method for Determination of Veterinary Drug Oxyclozanide by Electrochemical Sensor and Its Application to Pharmaceutical Formulation

A novel highly selective, sensitive and simple analytical technique was recommended for the investigation of anthelmintic veterinary drug oxyclozanide based on square wave anodic stripping voltammetry (SWASV) by using a carbon paste electrode (CPE). According to the cyclic voltammetric data, the oxidation and electron transfer processes of oxyclozanide were found as irreversible and adsorption-controlled, respectively. The voltammetric anodic peak response was characterized with respect to pH, accumulation potential, accumulation time, frequency and pulse amplitude, etc. Under these optimized experimental conditions, the anodic peak density of oxyclozanide was linear to oxyclozanide concentrations in the range from 0.058 to 4.00 mg/L. The described electrochemical method was successfully carried out for the oxyclozanide in pharmaceutical formulation and tap water with mean percentage recovery of 101.5 % and 102.2 %, respectively. The results of pharmaceutical formulation studies were statistically compared to the high-performance liquid chromatographic method.

Comparative pharmacokinetics of levamisole-oxyclozanide combination in sheep and goats following per os administration

Since there is no registered anthelmintic drug available for use in goats, extra-label use of drugs is a common practice in most countries. The aim of the present study was to compare the pharmacokinetic disposition of levamisole (LVM)-oxyclozanide (OXZ) combination in sheep and goats following per os administration. Goats (n = 8) and sheep (n = 8) 12- to 16-months-old were used for this study. The animals received tablet formulation of LVM and OXZ combination orally at a dose of 7.5 mg/kg and 15 mg/kg body weight, respectively. Blood samples were collected by jugular vein at different times between 5 min and 120 h after drug administrations. The plasma concentrations of LVM and OXZ were analyzed by HPLC following liquid-liquid phase extraction procedures. The plasma concentrations and systemic availabilities of both LVM and OXZ in goats were lower and the plasma persistence of LVM was shorter compared with those observed in sheep. Terminal half-lives (t1/2λz) of both molecules are shorter in goats compared with those in sheep. Goats treated with LVM-OXZ combination at the recommended dose for sheep may result in a reduced efficacy, because of under-dosing, which may increase the risk of drug resistance in parasites. Increased or repeated dose could be a strategy to provide higher plasma concentration and thus to improve the efficacy against the target parasites in goats compared with sheep. However, some adverse reactions may occur since LVM has relatively very narrow therapeutic index due to its nicotine-like structure and effect.