Study to Compare Blood Levels of Ceftriaxone Given by Suppository or Injection.

Phase 1, three-way cross-over, randomised, open label comparison of intravenous versus two rectal dosage forms of ceftriaxone in 37 healthy Thai adults. The following regimens will be evaluated in random order in all participants: A. Ceftriaxone (Roche ®) 500mg (slow intravenous injection) B. Ceftriaxone rectal dosage form test formulation 1-hard-shell gelatin capsule (1 x 500mg) C. Ceftriaxone rectal dosage form test formulation 2-rectodispersible mannitol-based tablet (1 x 500mg) Possible schedules: ABC, ACB, BAC, BCA, CAB, CBA. Each recipient will receive a single treatment dose of each of the three formulations in an order predetermined by a computer generated randomisation list. This will be a constrained randomization which ensures approximately balanced proportions for all six schedules (either 6 or 7 participants per schedule). There will be 7-28 days washout period between doses. The last follow up visit is 28 (+ 2) days after final dose. Participants lost to follow-up or unevaluable for any reason before completion of pharmacokinetic sampling after the final dose will be replaced at the discretion of the investigators with another participant of the same population, if either sample size or completeness of dataset is compromised. This study is funded by the Medical Research Council. The grant reference number is MR/W021560/1