Figure 2.
In vivo lung microdialysis of inhaled mAbX. a) Scheme of the experimental setup. Prior to microdialysis, pulmonary deposition in each animal was determined by scintigraphy imaging. Inhalation of mAbX (3 mL of 10 mg/mL solution) was done in conscious animals, and the microdialysis probe was then immediately inserted in the lung parenchyma by thoracic surgery. Animals were maintained under mechanical ventilation and prolonged anesthesia for up to 54 hours and were monitored continuously during this period. Blood and microdialysate were collected on a predefined schedule (every 6 and 3 hours, respectively) to analyze mAbX and urea (as a control of probe permeability). At the end of the experiment, animals were sacrificed by exsanguination and lungs were excised. b) Lung deposition with the customized mesh nebulizer in conscious macaques. Scintigraphic imaging of a representative animal that received the formulation without the antibody spiked with99mTc-DTPA as a tracer and the dose (in %, right) deposited in the different regions of interest (ear/nose and throat (ENT), lungs, stomach) determined from the digitalized images using lung tissue attenuation coefficients. All results are expressed as the percentage of the activity loaded in the nebulizer and correspond to the median [IQR] (n = 3 animals). c) Urea ratio to assess the probe permeability in vivo. Urea was measured in the microdialysate and in the blood throughout the experiment. Results are expressed as the ratio of urea in the microdialysate to blood urea and correspond to the median [IQR], n = 3 animals. n.s. non-significant (Friedman test).