Effect of formulation parameters on pharmacokinetics, pharmacodynamics, and safety of diclofenac nanomedicine

This study reports the development of a nanoformulation of diclofenac sodium, a potent non-steroidal anti-inflammatory drug, at its clinical dose, utilizing a FDA approved polymer, hydroxyethyl starch. The study specifically focused on the control of pharmacokinetics, pharmacodynamics, and biodistribution by particle surface functionalization and alteration of excipient levels in the final formulation. Stable diclofenac sodium-loaded hydroxyethyl starch nanoparticles (nanodiclo) of size 170 ± 5 nm and entrapment efficiency 72 ± 3% were prepared. Free diclofenac, nanodiclo, nanodiclo surface functionalized by PEGylation, nanodiclo with excipients removed, and finally PEGylated nanodiclo with excipients removed were all tested comparatively at two different doses. The results showed substantial impact of both excipients and PEGylation on the pharmacokinetics and pharmacodynamics in vivo. Further, the results proved that excipient removed PEGylated nanodiclo at lower dose achieved clinical therapeutic levels in blood for up to 120 h, with minimal accumulation in critical organs, and much better efficacy than other controls.