Production of Carboxymethylated Xanthan Gum Microemulsions for Eugenol Encapsulation

Eugenol is a compound with well‐known bioactivity; however, its volatility limits its therapeutic applicability. In the present study, carboxymethylated xanthan gum (CXG) is synthesized and characterized regarding its degree of substitution (DS) by potentiometric titration and by infrared spectroscopy (FTIR). Oil‐in‐water xanthan gum‐based nanoemulsions enriched with eugenol have been prepared in variable conditions, using XG (xanthan gum) and CXG as matrices to produce a stable formulation with an effective ovicidal activity. Physical–chemical characterizations are performed, besides ovicidal activity on Haemonchus contortus, the main gastrointestinal nematode infecting and affecting small ruminants. FTIR results indicate the insertion of the carboxymethyl groups in the structure of xanthan gum through the peaks at 1100 and 1600 cm−1, and titration shows a DS of 1.25 for CXG. XG and CXG emulsions present stability over 30 days and encapsulation efficiency higher than 50%. The CXG2 emulsion (CXG:oil:tween 4:2:1) shows better stability concerning the lower zeta potential value, and the morphology shows domains with smaller sizes in the range of 1.41 µm. The evaluated nanoemulsions show ovicidal activity against H. contortus, which encourages their future use as an alternative to control haemonchosis in sheep and goats.