Veterinary compounding: the impact of different gelling agents on the rheological characteristics and release kinetics from meloxicam oral gels in the treatment of cats

Worldwide, the growing number of pets has increased the use of veterinary drugs, as well as individualised therapy such as compounded drugs. If a suitable formulation or drug is not registered for veterinary species, drugs are compounded. This also includes pharmaceutical forms which are easy to administer, such as semi-solid preparations (gels and pastes) for oral use in order to enhance drug administration and adherence. The number of non-steroidal drugs (NSAIDs) approved for use in cats is relatively small. NSAIDs represent the largest group of drugs with adverse drug experience, but meloxicam has advantages in relation to all of them because of its safety for use in cats. In this study, the pharmaceutical-technological characterisation of oral gels for cats made with different gelling agents (carbomer, xanthan gum, carmellose sodium and hypromellose) was undertaken. Subsequently, four different samples were prepared and designed for veterinary use (using meloxicam, gelling agents and taste enhancer), and then the pH value, rheological characterisation and drug release were determined. The results demonstrated that addition of the taste enhancer influenced the rheological properties of the tested oral gels. It was found that the rate of meloxicam release was the highest from the oral gel prepared with carbomer (Carbopol (R) 974P), where complete meloxicam dissolution was observed after 5 minutes. On the basis of these results, it was concluded that Carbopol 974P has a certain advantage over the other gelling agents used in this study. Further work is required to assess the palatability of the oral gel for cats in clinical settings.