Study comparing anti-tuberculosis drug levels in saliva, plasma, and urine in patients

Levofloxacin pharmacokinetics in saliva characterised using a population PK model. Relevant parameters include description of compartment, covariates and estimation of AUC or Cmax.

Therapeutic drug monitoring (TDM) is recommended for anti-tuberculosis (TB) drugs. Some drugs can penetrate into saliva and urine sufficiently enough to be used as alternative sampling. Our primary aim is to develop a salivary pharmacokinetic model for levofloxacin. The secondary objectives are to study the salivary penetration ratios for TB drugs, determine the relationship between the genotype of NAT2 and isoniazid level, and determine the feasibility of using saliva or urine for TDM. A prospective, open-label, observational study will be conducted in 30 adult patients receiving TB drugs. Plasma, saliva, and urine samples will be collected around week 2 for drug analysis. The population PK model will be developed using Nonlinear Mixed Effects Modeling (NONMEM®). Expected outcomes include a salivary pharmacokinetic model for levofloxacin, the relationship between NAT2 genotype and isoniazid level, and an assessment of the feasibility of using saliva and/or urine for TDM of TB drugs.