![]() Briefly, peripheral blood monocytes were obtained by leukapheresis from HIV-1/2 and hepatitis B seronegative donors and purified by countercurrent centrifugal elutriation. Human peripheral blood monocytes were obtained and cultured as described. Notably, the process can be adapted to other ligand-targeted delivery systems and be of broad utility in the production of targeted drug crystals. The resultant FA decorated nanoformulated CAB (FA NCAB) demonstrated high particle integrity and drug loading with potential for large-scale production. ![]() The optimized manufacturing scheme obviates the need for purification. The chemical structure of CAB is illustrated in Figure 1. These make CAB an excellent component of any LA-ART regimen. CAB is a novel highly potent integrase strand transfer inhibitor with low aqueous solubility, high melting point and protein binding and a long systemic half-life. To address these limitations, we developed a simplified, scalable and reproducible production scheme for macrophage-targeted nanoART using CAB as a model compound. In fact, purification by differential centrifugation, filtration, dialysis or chromatography is tedious and provides limitations in the preparation of ligand-targeted formulations. However, high-speed centrifugation may cause particle aggregation and limit resuspension and large-scale production. The process is essential for targeting as unbound FA-P407 may compete with FA-decorated nanoparticles for receptor binding. Excessive FA-P407 was then removed by differential centrifugation. After high-pressure homogenization, FA conjugated P407 (FA-P407) coats the nanosized drug crystals, presenting FA on the particle surface. FA was covalently conjugated to hydrophilic termini of amphiphilic poloxamer 407 (P407), which serves as a stabilizer to prevent aggregation of drug crystals. Indeed, previous studies by our group have demonstrated that FA decorated nanoparticles can improve PK profiles and antiretroviral activity of ART. As an example, folic acid (FA) can be used as a ligand to target folate receptor-β expressed on the surface of activated macrophages. By attaching ligands that bind to specific cell receptors, targeted nanoparticles can better reach and release therapeutic agents at the disease site. One means to achieve macrophage targeting is by creating ligand-targeted nanoparticles. Macrophages have a long lifespan and are less sensitive to virus-induced cytopathicity and thus readily serve as drug sanctuaries. The highly mobile macrophages can also be recruited to sites of infection and inflammation enabling cell cargoes to move across physiological barriers. Slow release of drug from macrophages allows for sustained drug levels thus affecting long-term viral suppression. Herein, macrophages serve as ‘Trojan horses’ carrying crystalline ART to endosomal cell compartments. To further improve LA-ART delivery, our laboratory developed cell-targeted LA nanoformulated ART (nanoART). Variant pharmacokinetic (PK) profiles and lack of penetration into mucosal and viral reservoir tissues could also affect therapeutic outcomes and the emergence of viral resistance. ![]() Injection site reactions are the most common adverse event and a reason for patient therapeutic withdrawal. Nevertheless, two injections of a 2- or 3-ml volume are required to achieve desired monthly or bimonthly dosing, respectively. The formulation strategy produces pure nanosized drug crystals stabilized by surfactants with high drug loading. CAB and RPV are potent antiretroviral drugs with low aqueous solubility allowing both to be formulated into 200 or 300 mg/ml wet-milled suspensions. Indeed, LA cabotegravir (CAB) and rilpivirine (RPV), the first LA-ART combination, demonstrate comparable efficacy and safety to daily oral three drug regimens as seen, so far, in Phase II clinical trial. LA-ART also positively affects patient privacy by reducing social stigmas associated with daily regimens. Notably, transition from daily oral to monthly or bimonthly injections provide consistent plasma drug concentrations and may combat drug resistance. ![]() After parenteral injection, LA-ART provides month-long effective plasma drug concentrations overcoming obstacles in regimen adherence. Long-acting (LA) antiretroviral therapy (ART) is being developed for the treatment and prevention of HIV infection.
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