The current study examines the passive pulmonary targeting efficacy and retention of 6μm polystyrene (PS) microparticles (MPs) covalently modified with different surface groups [amine (A-), carboxyl (C-) and sulfate (S-)] or single (PEG1-) and double (PEG2-) layers of α,ω-diamino poly(ethylene glycol) attached to C-MPs. The ζ-potential of A-MPs (-44.0mV), C-MPs (-54.3mV) and S-MPs (-49.6mV) in deionized water were similar; however PEGylation increased the ζ-potential for both PEG1-MPs (-18.3mV) and PEG2-MPs (11.5mV). The biodistribution and retention of intravenously administered MPs to male Sprague-Dawley rats was determined in homogenized tissue by fluorescence spectrophotometry. PEG1-MPs and PEG2-MPs demonstrated enhanced pulmonary retention in rats at 48h after injection when compared to unmodified A-MPs (59.6%, 35.9% and 17.0% of the administered dose, respectively). While unmodified MPs did not significantly differ in lung retention, PEGylation of MPs unexpectedly improved passive lung targeting and retention by modifying surface properties including charge and hydrophobicity but not size.
All Science Journal Classification (ASJC) codes
- Pharmaceutical Science
- Passive pulmonary targeting
- Poly(ethylene glycol)
- Rigid non-biodegradable microparticle