Objective: To study the pharmacokinetics of ofloxacin using salivary drug concentration when
administered alone or in combination with rifampicin (R), isoniazid (H) and pyrazinamide (Z) and
also to assess the saliva to plasma concentration ratio.
Material and Methods: Twelve healthy male volunteers were investigated on four different occasions
with an interval of at least one week between occasions. They were administered ofloxacin,
either alone or in combination with R, H and Z. A partially balanced incomplete block design was
adopted and the subjects were randomly allocated to each group. Salivary and plasma concentrations
of ofloxacin were measured at 1, 2, 3, 6 and 8 h after drug(s) administration using validated
methods.
Results: There were no significant differences between various pharmacokinetic parameters when
ofloxacin was administered alone or in combination with R, H and Z. The mean saliva to plasma
ratio of ofloxacin concentration was around 0.6. The bioavailability indices of ofloxacin in the
saliva and plasma were similar in all the groups.
Conclusion: Several pharmacokinetic parameters could be calculated using salivary concentrations
of ofloxacin. The determination of ofloxacin levels in saliva may be useful in therapeutic
drug monitoring and pharmacokinetic studies