Interaction of vitamin B1 and phenylalanine on the pharmacokinetics of ciprofloxacin using bioassay in rabbits

Abstract

This pharmacokinetic study was carried out in rabbits following single oral administration of ciprofloxacin to study kinetic behaviour of ciprofloxacin in the presence of vitamin B1 and selected essential amino acid phenylalanine. Rabbits weighing 2-4 kg were randomly assigned to 5 groups of 6 each. Group 1 served as blank without any treatment. Group 2 served as ciprofloxacin control whereas Group 3, 4 and 5 rabbits were co-administered with thiamine (80 mg/kg), phenylalanine (48 mg/kg), combination of thiamine and phenylalanine along with ciprofloxacin (40 mg/kg) orally. Blood samples were collected at predetermined time intervals up to 24 h, and plasma was used for estimation of ciprofloxacin through bioassay. Results obtained from the experiment revealed that rabbits of Group 3, 4 and 5 showed improved levels of Cmax 4.74±0.17, 3.00±0.22, 2.18±0.12 µg/mLand AUC 20.30±5.19, 10.09±1.48, 12.85±1.34 µg.h/mL, respectively when compared to Cmax (2.10±0.14 µg/mL) and AUC (5.90±0.81 µg.h/mL) in Group II rabbits. PK-PD integration of the present study revealed that Cmax: MIC>8, AUC: MIC>125 in Group 3, 4 and 5 implying that the co-administration of vitamin B1 and phenylalanine and their combination improves the antibacterial activity and reduces the development of resistance at the selected dose of ciprofloxacin.