Doxycycline is a broad-spectrum antibiotic. The development of a polymer matrix that can allow for the controlled release of this drug can bring many benefits to veterinary and human medicine. For this reason, in the present study doxycycline was encapsulated in situ with gelatin through thermal treatments performed in inverse suspension, using distinct gelatin concentrations in the suspended aqueous phase. To characterize the performances of the obtained products, controlled release tests were performed. The effect of adding formaldehyde and glucose into the reaction medium to enhance gelatin crosslinking was analyzed, although obtained results indicated that addition of crosslinking agents is not necessary because addition of doxycycline is sufficient to promote the physical gelatin crosslinking. POLYM. ENG. SCI., 2017. (c) 2017 Society of Plastics Engineers