Depending upon the study objectives, protocols may include whole body and regional imaging using planar scintigraphy, or SPECT techniques. Following dosing, the deposition, residence, clearance and dispersion of the dosage form can be defined. The scintigraphic analysis can also be complimented with expertise in pharmacokinetic and pharmacodynamic evaluations, drug assay development and bioanalysis.

In the respiratory tract the performance of delivery systems is assessed by evaluation deposition and residence in the oropharyngeal and central and peripheral regions of the lung. Furthermore, physiological functions such as mucociliary clearance may be studied using this technique.

In the case of inhalation systems great care is taken to ensure that subjects are trained and competent in the use of the inhaler being evaluated, this is critically important for single breath delivery systems e.g. pMDI and DPI. CSL can facilitate electronic monitoring of the subjects' inspiratory manoeuvre during drug delivery. This is achieved by unobrusively locating a pressure probe in the mouthpiece of the device and connecting a micromanometer. Real time inspiratory flow information can then be displayed to the subject during training and dosing. An electronic record is recorded to enable compliance with pre-defined inspiratory parameters, i.e. inhaled flow rate, inhaled volume to be demonstrated. This technique can also be used for nebuliser systems where the dose is delivered over multiple breaths.

Case Studies:

   
Images showing real time inspiratory profiles during dose administration via a novel DPI. On three dosing occasions the volunteer targeted inhalation flow rates of 15, 30 and 60 L/min (shown from left to right).   Graph showing real time inspiratory profiles during dose administration via a novel DPI. On three dosing occasions the volunteer targeted inhalation flow rates of 15, 30 and 60 L/min

 

Images showing time dependent mucociliary clearance of radiolabel from the lungs of a healthy volunteer

 

 

Time sequenced images showing the utility of gamma scintigraphy in assessing drug effects on physiological function. The images show time dependent mucociliary clearance of radiolabel from the lungs of a healthy volunteer.