Reformulation of anti-tuberculosis drugs into dry powder particles for inhalation is a novel strategy that aims to
increase therapeutically relevant drug concentration at the primary site of infection and to limit associated toxicity by
avoiding or minimizing first-pass metabolism. Development of such formulations ultimately requires quantified evidence
of the deposition, absorption and clearance of inhaled active ingredient. In this context, we investigated the potential of
radiolabelling particles with 153Sm for subsequent gamma imaging, and to demonstrate that the technique is not detrimental
to particle integrity. The study showed that the known properties of spray dried leucine (a major constituent of an inhalable
capreomycin formulation) for deep lung inhalation are not altered by incorporation of samarium-chloride (SmCl3)
at 10% (w/w), or by neutron activation of particles that include stable 152SmCl3. SEM imaging indicated that the particle
morphology was homogeneous and spherical after neutron activation. No discoloration of the samples or a change in dry
powder particle size at 5 minutes occurred, provided the optimized formulations were activated for only 1 minute. Activation
for 1 minute still provides enough 153Sm for imaging purposes.
Keywords: Gamma imaging, 153Sm radiolabel, spray dried powder particles, pulmonary drug delivery, tuberculosis, leucine,
capreomycin, human immunodeficiency virus (HIV), multi-drug resistance, Neutron Activation, Chemical, Reagents, chromatography (HPLC), Samarium Formulation, homogeneous.
Rights & PermissionsPrintExport