Telithromycin (HMR 3647) is a novel ketolide antimicrobial with good activity against both common and atypical respiratory pathogens, including many resistant strains. This randomized, three-period crossover study determined the dose proportionality of telithromycin pharmacokinetics after single and multiple dosing in healthy subjects. In each treatment period, subjects received a single oral dose of 400, 800 or 1,600 mg of telithromycin followed 4 days later by the same dose once daily for 7 days. Blood and urine samples were taken throughout the study for determination of pharmacokinetic parameters for telithromycin and RU 76363, its main metabolite. Telithromycin and RU 76363 achieved steady state within 2 to 3 days of once-daily dosing. A slight accumulation of telithromycin was observed after 7 days of therapy, with values of the area under the concentration-time curve from 0 to 24 h approximately 1.5 times higher than those achieved with the single dose. The pharmacokinetics of telithromycin and RU 76363 deviated moderately from dose proportionality. At a dose of 800 mg/day, telithromycin attained mean maximal and trough plasma concentrations of 2.27 and 0.070 mg/liter respectively. Elimination was biphasic; initial and terminal half-lives were 2.87 and 9.81 h for the 800-mg dose. Study medication was well tolerated, although adverse events tended to be more frequent at the 1,600-mg dose. This study showed that telithromycin was generally well tolerated and suggests that a once-daily 800-mg oral dose of telithromycin maintains an effective concentration in plasma for the treatment of respiratory tract infections involving the key respiratory pathogens.

Telithromycin is an innovative antibacterial designed for the treatment of community-acquired respiratory tract infections. This study assessed the effect of food on the bioavailability of a single oral dose of telithromycin 800 mg in healthy male subjects. Male volunteers aged 18-45 y were recruited for an open-label, single-dose, 2-period, cross-over study. In each trial period, subjects received a single oral dose of telithromycin 800 mg after an overnight fast, or after a standard high-fat breakfast. A washout period of 6-8 d separated the 2 study periods. All 18 subjects recruited (mean age 30.7 y) completed the study. Telithromycin was rapidly absorbed, reaching maximum plasma concentrations within a median of 2.50 and 2.25 h in the fasting and non-fasting states, respectively. There was no statistical difference between the non-fasting and fasting states for any of the pharmacokinetic parameters measured. The mean plasma telithromycin concentration versus time profiles for the non-fasting and fasting phases were almost superimposable. For the maximum plasma concentration and area under the curve from time 0 to infinity, the 90% confidence intervals for the mean non-fasting:fasting ratios were 83-116 and 101-123 mg x h/l, respectively; these are within 80-125% of the bioequivalence range. Telithromycin was well tolerated. The bioavailability, rate and extent of absorption of the new ketolide antibacterial telithromycin were unaffected by food.

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The bioanalytical scientist plays a key role in the project team for the drug development of biotherapeutics from the discovery to the marketing phase. Information from the project team members is required for assay development and sample analysis during the discovery, preclinical and clinical phases of the project and input is needed from the bioanalytical scientist to help data interpretation. The European Bioanalysis Forum target team 20 discussed many of the gaps in information and communication between the bioanalytical scientist and project team members as a base for providing a perspective on the bioanalytical scientist's role and interactions within the project team.