• Comparison between the relative permeability coefficients of RIF and KM in pathologically defined large caseous necrotic nodules.
  

• Comparison between the relative permeability coefficients of INH, PZA, and MXF in caseous necrotic nodules to that of RIF and KM; comparison between the relative permeability coefficients of RIF, KM, INH, and MXF.
  

Drug: RIF
N/A
Drug: INH
N/A
Drug: PZA
N/A
Drug: KM
N/A
Drug: MXF
N/A

It takes 6 to 24 months of intensive combination therapy to cure tuberculosis (TB) with antibiotics that have proven activity in vitro. In contrast, many pulmonary infectious diseases can be cured following single drug treatment with similar drugs for only one to a few weeks. We hypothesize that the unusual complexity of TB lesions and the degree of sequestration of TB bacilli within these lesions may limit access of the drugs to their site of action, leading to treatment failure, long treatment duration and the emergence of drug resistance. To test the hypothesis that drug maldistribution into lesions impacts on treatment duration and failure, we propose to examine the lesion-specific penetration properties of 5 standard anti-TB drugs in the lungs of subjects selected for lung surgery. The study is designed to understand what lesion types are the most difficult to penetrate. This aspect of TB drug pharmacokinetics has been largely neglected so far, probably owing to the lack of adequate technology and the limited availability of human TB lesion samples. Fifteen patients who elect lung resection surgery will be asked to participate in the study. Consented subjects will receive 5 first and second line anti-TB drugs concomitantly at 1 of 5 pre-determined times prior to surgery. At the time of resection, drug levels will be measured in plasma, in uninvolved lung tissue and in lesions using standard analytical methods as well as imaging Mass Spectrometry (MS) where drug concentration gradients can be visualized across tissue sections. The major aim of this study is to determine actual concentrations and permeability coefficients of the 5 study drugs in various lesion types contained within subjects' surgically removed lung tissue. Data analysis will also provide the relative exposure of each drug in plasma versus lung tissue and lesion. If conclusive, the results may be taken into consideration when selecting drug doses and dosing regimens. Additionally, images generated by standard of care (SOC) High Resolution Computed Tomography (HRCT), and Dynamic MRI for each subject will provide information regarding lesion structure and anatomy, lesional blood flow and microvascular function.

Lesion-specific correlations will be established between CT radiology and drug pharmacokinetic (PK) to identify which histopathologic lesion types may be particularly difficult to sterilize and to evaluate the potential impact of drug penetration on treatment outcome. The long term goal of this study is to identify the factors behind poor lesion penetration, so that new agents can be optimized with better penetration properties to target harder-to-sterilize lesion' types.