Innovative Chitosan-Based Formulation for Controlled Release of Enrofloxacin: Pharmacokinetic Analysis in Rabbits

The present study was conducted to evaluate the pharmacokinetics (PK) of a novel triple-layer formulation of enrofloxacin (ENR) compared to a conventional ENR formulation following subcutaneous (SC) administration in rabbits as an animal model. The triple-layer formulation comprised chitosan and β-glycerophosphate (β-GP) and was cross-linked with glutaraldehyde. The PK of the conventional ENR formulation was assessed after SC administration at a dosage of 10 mg/kg in rabbits; these results were subsequently compared with the disposition kinetics of the ENR film formulation. High-performance liquid chromatography (HPLC) was employed to quantify ENR concentrations in plasma, and non-compartmental analysis was utilized to calculate the PK parameters. The results indicated that the film formulation facilitated sustained drug release. The mean residence time (MRT) for ENR with the film formulation (F1) was significantly enhanced, presenting a 29-fold increase compared to the conventional formulation (p < 0.05). Although the C_max of the conventional ENR formulation was significantly higher than that of film F1 (by a factor of 18.5), the T_max value for film F1 was significantly greater than that of the conventional drug, showing an increase of 5.1 times. In conclusion, the triple-layer film demonstrated favourable characteristics for the sustained delivery of ENR, particularly exhibiting a high MRT. Consequently, the use of films as a delivery system may provide an effective strategy to extend the pharmacological activity of ENR in animals.