Flow cytometric analysis of the physical and protein-binding characteristics of solid drug nanoparticle suspensions.
Oral and intramuscular sustained-release antiretroviral solid drug nanoparticles (SDNs) are in development but there is limited understanding of whether nanoparticles or dissolved drug predominate systemically. A flow cytometric method was developed to analyze SDNs in biological fluids such as plasma, including the putative formation of a protein corona. SDNs were found to be stable in plasma and could be observed using the techniques developed here. In addition, transferrin, fibrinogen and albumin were found to be associated with SDNs upon incubation. This methodology has enabled us to determine protein interactions of SDNs in solution without the requirement of separation from the matrix. This will enable further studies of their biological fate.