Sentence: To assess plasma steady-state pharmacokinetics ( PK ) of rifampicin , isoniazid , saquinavir and ritonavir in HIV and tuberculosis ( TB ) co-infected patients , and investigate potential interactions between TB drugs and protease inhibitors ( PIs ) .
Drug combination annotation:
[{'class': 'COMB', 'spans': ['isoniazid', 'saquinavir', 'ritonavir', 'rifampicin'], 'is_context_needed': True}]