Human peripheral blood monocytes were obtained and cultured as described [21 (link)]. Briefly, peripheral blood monocytes were obtained by leukapheresis from HIV-1/2 and hepatitis B seronegative donors and purified by countercurrent centrifugal elutriation. Monocytes were cultured in Dulbecco's modified eagle's medium supplemented with 10% heat-inactivated pooled human serum, 10 μg/ml ciprofloxacin, 50 μg/ml gentamicin and 1000 U/ml recombinant macrophage colony-stimulating factor for 7 days to promote differentiation into macrophages. Macrophages were treated with 100 μM CAB nanoformulations. At predetermined time points, monocyte-derived macrophages (MDM) were washed three-times with sterile phosphate-buffered saline (PBS) and scraped into 1 ml PBS. Cell pellets were collected by centrifugation at 1000 × g for 8 min, followed by probe sonication in 200 μl of HPLC grade methanol to extract CAB. CAB concentrations were determined using a Waters ACQUITY ultra performance liquid chromatography (UPLC) H-Class System with TUV detector and Empower 3 software (Milford, MA, USA) [22 (link)].