Comparative evaluation of polymeric nanoparticles of rifampicin comprising Gantrez and poly(ethylene sebacate) on pharmacokinetics, biodistribution and lung uptake following oral administration.

The present study reports the comparative pharmacokinetic evaluation and biodistribution of rifampicin (RIF) following oral administration of nanoparticles of a bioadhesive polymer, Gantrez and a hydrophobic polymer poly(ethylene sebacate) (PES). A specific objective of the study was to evaluate lung uptake of the nanoparticles following oral administration. Nanoparticles were obtained in the size range 350-450 nm with rifampicin loading of 12-14% w/w. Zeta potential confirmed colloidal stability. PES nanoparticles revealed high macrophage uptake compared to Gantrez nanoparticles, and direct correlation was observed between hydrophobicity (contact angle) and macrophage uptake (r2 -0.940). Enhanced RIF uptake with folic acid anchoring suggested folate receptor mediated uptake. RIF nanoparticles exhibited significantly higher Cmax and AUC, delayed Tmax and sustained release compared to plain RIF. More importantly the plasma concentration of RIF with the nanoparticles was significantly greater than the MIC of RIF (0.25 microng/mL) over 24 h. While gamma scintigraphy revealed higher lung accumulation of nanoparticles, the concentration with Gantrez nanoparticles was significantly higher. HPLC evaluation of lung concentration correlated with scintigraphy data. The significantly higher bioavailability and lung accumulation with Gantrez nanoparticle over PES nanoparticles was attributed mucoadhesion and high affinity of Gantrez to the Peyer's patches. Our study suggests Gantrez nanoparticles as a promising carrier for enhancing lung accumulation of drugs.