PK-PD modelling of norfloxacin after oral administration in rabbits

Norfloxacin posses a wide spectrum of activity, excellent tissue penetration and is rapidly bactericidal at low concentrations and hence an attempt was made to integrate reported pharmacodynamic data with pharmacokinetic data of norfloxacin after oral administration in rabbits to determine its effectiveness against common bacterial pathogens infecting rabbits. Pharmacokinetic data were obtained after a single per oral administration of norfloxacin @ 100mg per kg. Plasma drug concentrations were determined using high performance liquid chromatography (HPLC). From PK-PD integration, it is observed that norfloxacin is highly effective against gram negative infections caused by Pasteurella multocida (AUC/MIC and Cmax/MIC ratio of 133.5 and 111.5 respectively), its efficacy against Salmonella spp., E. Coli, Shigella spp. and Haemophilus influenza is moderate. However, per-oral administration of norfloxacin is not suitable to contain tested gram positive bacterial pathogens infecting rabbits.