The present study describes the development of a good manufacturing practice (GMP)-grade liposomal nanotherapy containing prednisolone phosphate for the treatment of inflammatory diseases. After formulation design, GMP production was commenced which yielded consistent, stable liposomes sized 100 nm ± 10 nm, with a prednisolone phosphate (PLP) incorporation efficiency of 3%-5%. Pharmacokinetics and toxicokinetics of GMP-grade liposomal nanoparticles were evaluated in healthy rats, which were compared to daily and weekly administration of free prednisolone phosphate, revealing a long circulatory half-life with minimal side effects. Subsequently, non-invasive multimodal clinical imaging after liposomal nanotherapy’s intravenous administration revealed anti-inflammatory effects on the vessel wall of atherosclerotic rabbits. The present program led to institutional review board approval for two clinical trials with patients with atherosclerosis.