Penalization and Color Code Technical Approaches for Method Greenness and Whiteness Appraisal in Veterinary Medication: Assay of Toltrazuril Suspension.

Background: Intestinal coccidiosis is a debilitating disease in poultry and livestock, leading to economic impact worldwide. Coccidiosis is prevented and treated in broilers by the inclusion of anticoccidials in feed. Toltrazuril is administered in potable water to treat coccidiosis.

Objective: Three robust analytical methods for the quantitation of toltrazuril in pure and pharmaceutical formulations are developed. Furthermore, ecological metrics, either penalization- or color-code-based techniques, are applied for the appraisal of assays.

Methods: First, second-derivative (Δλ; 5 nm) spectrophotometric method is used. Toltrazuril is measured from peak to peak at 244-260 nm within a linearity range of 5-25 μg/mL. The second method is an HPTLC analysis performed on an aluminum sheet of silica gel using ethyl acetate-methanol-ammonium chloride buffer-water (8:1:0.5:0.5, by volume respectively) as the elution phase. Toltrazuril, at a retardation factor of 0.66 ± 0.01, is linearly determined in the range of 1-9 μg/spot at 243 nm. The third method is reversed-phase HPLC with diode array detection, using an Agilent C18 column (5 μm, 4.6 × 150 mm) in isocratic elution mode at 1 mL/min flow rate with a mobile phase of acetonitrile and water in a ratio of 80:20 (v/v). Toltrazuril elutes at a retention time of 2.58 ± 0.1 min and is linearly determined at 243 nm in the range of 0.25-25 μg/mL.

Results: Calculated 2D-values and peak areas are highly correlated to their corresponding drug concentrations at coefficients: r > 0.999. All methods were International Council of Harmonization (ICH) validated and applied to the dosage form with satisfactory % recoveries (97-103%). Statistical comparisons versus reported one using t-test and F-test disclose insignificant variation. In examining greenness and whiteness norms, the proposed methods were evaluated and ranked alongside four different reported methods.

Conclusions: The proposed methods are green, accurate, and can be applied in routine QC for the determination of toltrazuril in pharmaceutical formulations.

Highlights: Intestinal coccidiosis substantially affects the chicken intestinal tract leading to reduced growth. Toltrazuril is used for the treatment and prevention of intestinal coccidiosis. Three robust, accurate, and precise analytical methods are developed for toltrazuril determination in pure and pharmaceutical formulations. All proposed methods were ecologically assessed and compared with published ones.