In an effort to improve treatment outcomes and shorten treatment duration, TB drug research has been aiming at redevelopment of existing first-line TB drugs (high dose rifamycins and pyrazinamide) and repurposing of available antibiotics (e.g. moxifloxacin, linezolid and clofazimine), alongside the development of new compounds (e.g. bedaquiline, delamanid, SQ109). The advantage of redeveloping and repurposing existing antibiotics is that results can be obtained rapidly and safety data are already available. Knowledge on the appropriate dose, plasma exposure and antimycobacterial efficacy are key components for adequate redevelopment and repurposing of TB drugs, and general TB therapy optimisation.