Background and Introduction The dispersible tablet formulation (DTF) of pretomanid has been developed to facilitate future use in children. This work aimed to assess the pharmacokinetics (PK) and relative bioavailability of the DTF compared to the marketed formulation (MF) and the potential influence of dose. Methods Pretomanid DTF was investigated in a single-dose, randomized, four-period, cross-over study, with 7 days of washout between doses. Forty-eight healthy volunteers were enrolled and randomized into one of two panels to receive doses either in the fasted state or after a high-fat meal. Each volunteer received doses of 10, 50, and 200 mg DTF, and 200 mg MF pretomanid. Blood samples for pharmacokinetic assessment were drawn following a rich schedule up to 96 h after each single dose. The study data from the panel receiving the high-fat meal were analyzed using a nonlinear mixed-effects modeling approach, and all data were characterized with noncompartmental methods. Results A one-compartment model with first-order elimination and absorption through a transit compartment captured the mean and variability of the observed pretomanid concentrations with acceptable precision. No significant difference in bioavailability was found between formulations. The mean absorption time for the DTF was typically 137% (86-171%) of that for the MF. The bioavailability was found to be dose dependent with a small positive and larger negative correlation under fed and fasted conditions, respectively. Conclusion Using data from a relative bioavailability study in healthy adult volunteers, a mathematical model has been developed to inform dose selection for the investigation of pretomanid in children using the new dispersible tablet formulation. Under fed conditions and at the currently marketed adult dose of 200 mg, the formulation type was found to influence the absorption rate, but not the bioavailability. The bioavailability of the DTF was slightly positively correlated with doses when administered with food.

Aim

Delamanid is a novel drug for the treatment of drug-resistant tuberculosis, manufactured as 50-mg solid and 25-mg dispersible tablets. We evaluated the effects of dispersing the 50-mg tablet, focusing on the relative bioavailability.

Methods

Delamanid, 50-mg tablets administered dispersed vs swallowed whole, was investigated in a phase I, four-period, crossover study. Two of three dose strengths of delamanid (25, 50 or 100 mg) were given to healthy adult participants, in both whole and dispersed forms, with a 7-day washout period. Blood samples were collected over 168 h after each dose. Delamanid and its metabolite DM-6705 were analysed with a validated liquid chromatography tandem mass spectrometry assay. The pharmacokinetics of both analytes were analysed using nonlinear mixed-effect modelling. Palatability and acceptability were determined using a standardized questionnaire.

Results

Twenty-four participants completed the study. The bioavailability of dispersed tablets was estimated to be 107% of whole tablets, with a 90% confidence interval of 99.7-114%, fulfilling bioequivalence criteria. The two formulations were not significantly different regarding either bioavailability or its variability. Bioavailability increased at lower doses, by 34% (26-42%) at 50 mg and by 74% (64-86%) at 25 mg, relative to 100 mg. The majority of participants (93%) found the dispersed formulation acceptable in palatability across all delamanid doses.

Conclusions

Dispersed 50-mg delamanid tablets have similar bioavailability to tablets swallowed whole in adult volunteers. This can be an option for children and other patients who cannot swallow whole tablets, improving access to treatment.

Aims: Moxifloxacin is a priority drug for treating rifampicin-resistant tuberculosis (RR-TB). We assessed the pharmacokinetics of a child-friendly, dispersible 100 mg tablet moxifloxacin formulation (dispersed in water) compared to the standard 400 mg non-dispersible formulation (crushed and suspended in water) in children and evaluated current dosing recommendations.

Methods: The CATALYST trial investigated the pharmacokinetics of moxifloxacin in children with RR-TB. Children were enrolled in South Africa, India and the Philippines. Intensive pharmacokinetic sampling was undertaken while children were taking the standard non-dispersible 400 mg moxifloxacin tablet formulation and repeated after switching to the novel dispersible formulation. Pharmacokinetic data were analysed using population pharmacokinetic modelling. Simulations were per- formed to evaluate moxifloxacin exposures in children compared to consensus adult reference exposures using current World Health Organization (WHO)-recommended doses and more recent model-based doses.

Results: Thirty-six children were enrolled [median age 4.8 (range 0.4–15) years and weight 15.6 (range 6.9–42.1) kg]. A two-compartment disposition model with first- order elimination and delayed absorption was developed. The bioavailability of dis- persible versus standard formulations fulfilled standard bioequivalence criterion (ratio 1.05 with 90% confidence interval 0.95–1.15). Simulations showed WHO- recommended doses achieved exposures similar to those in adults in children >10 kg, while children <10 kg may require 33%–56% higher doses to reach adult reference exposures.

Conclusions: Dosing recommendations for children can be the same for the dispers- ible paediatric and standard non-dispersible adult moxifloxacin formulation. The cur- rent WHO dosing recommendation risks underdosing moxifloxacin in children <10 kg. We propose optimized moxifloxacin doses for both formulations.