Florfenicol Recovery When Using Amphen® Oral Suspension In A Proportioner Compared To A Non-Nanonised Formulation

A field trial was carried out to compare the florfenicol concentration in the final drinking water and in the plasma of two different formulations of liquid florfenicol-containing products.

Pigs (with a mean bodyweight of 25.5 kg) were assigned to two treatment groups and housed in the same compartments under the same conditions. 

Table 1. Trial overview

In both groups, pigs were treated at 10 mg florfenicol/kg bodyweight/day for 5 days. The two stock mixtures had equal florfenicol concentrations and volumes at the start of the trial and were manually stirred for 20 seconds. Medicated water was consumed within 12 hours of administration using a proportioner set at a 1% injection rate (dilution 1:100). Water samples were collected from 10 nipples at 3, 6 and 10 hours after the start of administration to determine mean florfenicol recovery in the final drinking water. In addition, blood samples were taken from 10 pigs at 6, 9, 12 and 24 hours for determination of mean florfenicol plasma concentrations. 

• Visual appearance of the stock mixtures (Figure 1)
  • Amphen® Oral suspension (left): Excellent homogeneity throughout the administration period
  • Standard formulation (right): Substantial sedimentation of insoluble crystals starting immediately after mixing

Figure 1. Visual appearance of the two stock mixtures (picture taken 30 minutes after stirring)

• Florfenicol recovery in the final drinking water (Figure 2)

Figure 2. Florfenicol recovery in the final drinking water expressed as a percentage of the theoretically expected concentration at three time points after the start of administration

• Florfenicol concentrations in plasma (Figure 3)

Figure 3. Florfenicol concentrations in plasma at four time points after the start of administration

Conclusion

Standard florfenicol formulations are not suitable for use via proportioners. Amphen® Oral suspension, containing nanonised florfenicol, demonstrates outstanding homogeneity in such proportioners, resulting in superior recovery in both final drinking water and plasma. This explains the differences in clinical response observed in the field.