Albumin nanoparticles are promising candidates for drug delivery to the lungs. Previous studies on the clearance,
biocompatibility and biodistribution of albumin nanoparticles have demonstrated their ability to target drug delivery
to the lungs. We have demonstrated that therapeutically relevant compounds can be incorporated into albumin
nanoparticles, however a need for an optimised method and further characterisation was identified. In this study
we investigated two methods of manufacture: pre-loading and in situ loading of two new antimycobacterial
benzothiazinones (IR 20 & IF 274) with albumin nanoparticles. Nanoparticles were successfully manufactured
robustly with both methods. In situ loaded nanoparticles offered higher capacity to carry these antimicrobial
compounds: around 6 μg/mg compared to about 3 μg/mg for pre-loaded nanoparticles, despite similar drug
encapsulation efficiencies for IR 20 pre-loaded nanoparticles (54% compared to 46% for the in situ method). In
situ loaded nanoparticles also produced less drug loss during the purification process. This study has shown the
development of novel methods for synthesis of drug-loaded albumin nanoparticles which has demonstrated that
potent poorly-soluble, therapeutically-relevant compounds can be loaded into albumin nanocarrier formulations for
inhaled drug delivery.