Correct Dosing By Microgranulated Premixes

Homogenous distribution ensures correct dosing and contributes to responsible use of medicines. Superior homogeneity is demonstrated for microgranulated premixes compared to simple powder premixes, resulting in sufficiently high target tissue concentrations for all treated animals.

Microgranulation

Microgranulation is an innovative and unique formulation technology developed for Huvepharma® veterinary premixes. By applying this technology, the active is encapsulated in large and equally sized microgranules. Microgranulation of antibacterial and anthelmintic premix brands (Table 1) makes them completely different from standard powders in which the active ingredient is simply mixed with a carrier (Figure 1). 

Table 1. Overview of Huvepharma®'s microgranulated veterinary premixes

Figure 1. Visual appearance of a microgranulated (left) and a powder (right) premix

The main benefit of microgranulation is an even distribution of the active compound throughout the medicated feed without any demixing. This homogeneity results in correct dosing of all animals consuming the medicated feed. Underdosing may mean the treatment is ineffective, leading to longer or higher frequency treatment periods and increases the risk of antimicrobial resistance developing.

Microgranulated premixes demonstrate much better flowability and lower wall adhesion in the feed production and delivery systems. Furthermore, the protective nutshell around the active substance ensures pelleting stability (Figure 2). 

Figure 2. Benefits of microgranulation

Homogeneity

During production in the feed mill, transport by feed trucks and storage on farm, a medicated feed is transferred by pipelines over a long distance. This is a potential risk for demixing of the active substance.

A trial was set up in a renowned French institute to investigate the impact of microgranulation on the distribution of the active substance in a final feed. This was determined for two premixes both containing 100 g tiamulin hydrogen fumarate per kg: Vetmulin microgranulated premix and a standard powder premix.

These products were homogenously mixed with the feed, and their behaviour was evaluated by a vertical drop of the medicated feed. After the vertical drop, 10 samples were taken in five different layers at the top and at the bottom of the collector pot for the determination of the tiamulin content. Superior homogeneity was found in case of microgranulation with a 10-fold lower coefficient of variation (Figure 3 and Table 2). 

Figure 3. Tiamulin feed concentrations following the use of a microgranulated and a standard powder tiamulin-containing premix. Target = 200 ppm (red line)

Table 2. Mixing homogeneity and average tiamulin content following the use of a microgranulated and a standard powder premix

Elutriation rate

The elutriation rate gives a clear indication of the risk of demixing. This test method was performed three times for each product. The closer to zero, the better the homogeneity. 

A result closer to zero means that the concentrations at the top and at the bottom are closer together, indicating superior homogeneity after the drop. Microgranulation resulted in superior homogeneity while substantial demixing was observed with the simple powder premix.

The higher ratio of the powder formulation indicates a relatively higher tiamulin concentration at the top as dropping occurred at a slower rate and product followed the finest particles (Figure 4). 

Figure 4. Average elutriation rate and standard deviation following a vertical drop of two medicated feeds: Vetmulin microgranulated premix and a powder premix, both containing 100 g tiamulin hydrogen fumarate per kg (p < 0.05)

Conclusion

Microgranulation is an advanced formulation technology for veterinary premixes ensuring homogeneity of the active compound in medicated feed. Administering microgranulated premixes supports responsible use of veterinary products and sustainable livestock farming by correct dosing.