Pharmacokinetic Study of Two Oral Formulations of Levofloxacin in Healthy Male Volunteers

ABSTRACT: The objective of this study was to compare different pharmacokinetic parameters of a local (“X”) and reference (Tavanic) formulations of levofloxacin 250 mg tablets after oral administration of a single dose under fasting condition. Thirteen blood samples were collected from each of the eight Bangladeshi healthy male volunteers over 24 hours after oral administration of the drugs. Serum levofloxacin concentrations were determined by HPLC assay using UV detection, and pharmacokinetic parameters were determined by the non-compartmental method. Mean ± SD of Cmax, AUC0-24, AUC0-α, Tmax, t1/2, kel, were 4.33 ± 1.16 and 4.56 ± 1.51 µg/mL, 45.90 ± 8.74 and 37.77 ± 9.94 hr-µg /mL, 79.94 ± 32.80 and 66.85 ± 35.43 hr-µg/mL, 1.22 ± 0.49 and 1.28 ± 0.41, 19.90 ± 11.49 and 21.00 ± 16.39 hr, 0.04 ± 0.02 and 0.05 ± 0.03 hr-1 for the local (“X”) and reference formulation, respectively. From the paired t-test, the p-values for two formulations were found to be 0.182, 0.412 and 0.725 for AUC0-24, AUC0-α, and Cmax respectively. The 90 % confidence intervals of the mean of the difference between log-transformed values for Cmax were almost within the bioequivalence accepted range of 80 % to 125%, namely: (78.90%, 118.36%); but for AUC0-24 and AUC0-α the values were are beyond the acceptable range. (100.83%, 146.52%) and (94.34%, 157.89%) respectively. The results indicate that the two formulations are not bioequivalent for both the rate and extent of absorption