UTILIZATION OF SALIVARY CONCENTRATIONS OF CIPROFLOXACIN IN SUBJECTS WITH CYSTIC-FIBROSIS

Ciprofloxacin, an orally-absorbed fluoroquinolone is effective against multiply resistant Pseudomonas aerginosa in cystic fibrosis patients. It is the only practicable agent against extraintestinal salmonellosi s and shigellosis in developing countries. However, concern with the r isk of arthropathy in young children has restricted its use in pediatr ics. Pharmacokinetic studies with ciprofloxacin are limited in the ped iatric population. As a result, the dose and frequency of administrati on are not established in children. In this study the possibility of u sing salivary concentrations as surrogate measure of serum concentrati ons was investigated. A pediatric formulation of the drug (125 mg per capsule) was prepared and compared to 250 mg tablets. Relative bioavai lability was 105% (tablet/capsule). The time to peak salivary concentr ation and elimination rate from saliva were significantly different fr om serum (p < 0.01 and p <0.05 respectively). The linear regression an alysis of post-peak concentrations in serum and saliva yielded a slope of 1.25 and correlation coefficient of 0.83. It was also found that s alivary concentrations may be contaminated from drug retained in the o ral cavity. The conclusion was drawn that salivary concentrations coul d not be reliably used as a surrogate measure of serum levels for ther apeutic drug monitoring.