Transport of digoxin-loaded polymeric nanoparticles across BeWo cells, an in vitro model of human placental trophoblast

Abstract

Background: Fetal arrhythmias can lead to fetal congestive heart failure and hydrops fetalis. Digoxin (the first-line treatment) has low transplacental permeability and high risk of maternal side effects. Biodegradable digoxin-loaded PEGylated poly(lactic-co-glycolic acid) nanoparticles may increase digoxin transport across BeWo b30 cell monolayers (an in vitro model of trophoblast in human placenta) by reducing the drug's interaction with P-gp. Results/methodology: The nanoparticles showed high encapsulation efficiency and sustained release over 48 h. Transport studies revealed significantly increased permeability across BeWo cell layers of digoxin-loaded nanoparticles when compared with free digoxin. P-gp inhibition also increased the permeability of digoxin, but not digoxin-loaded nanoparticles.

Conclusion: This represents a novel treatment strategy for fetal cardiovascular disease which may improve maternal and fetal outcomes.

Figure 1.. In vitro drug release of digoxin from polyethylene glycol–poly(lactic-co-glycolic acid) nanoparticles (RGPd50105, 10% drug loading) over 48 h under sink conditions at 37°C in phosphate-buffered saline.

The inset shows the fit of the data to the Higuchi equation (as described in the ‘Release study’ subsection). Error bars represent the standard deviation (n = 3). PLGA: Poly(lactic-co-glycolic acid).

Figure 2.. Biocompatibility of blank polyethylene glycol–poly(lactic-co-glycolic acid) nanoparticles in BeWo cells at various concentrations after 4, 24 and 48 h of exposure, as assessed by the WST-1 colorimetric assay.

Triton X-100 was used as a negative control, and blank cell culture medium without nanoparticles was used as the positive control (set to 100% cell viability). The error bars represent the standard deviation (n = 6). PLGA: Poly(lactic-co-glycolic acid).

Figure 3.. Apparent permeability (P_e) for the transport of free digoxin (white bar) and digoxin-loaded polyethylene glycol–poly(lactic-co-glycolic acid) nanoparticles (RGPd50105, 10% drug loading, black bar) across BeWo cell monolayers in the apical (maternal) to basolateral (fetal) direction at the 2-h time point.

The transport studies were carried out at 37°C under cell culture conditions with stirring. P_e was also determined for both formulations in the presence of 100 μM verapamil, a P-gp inhibitor. Asterisks indicate significant differences from the permeability of free digoxin (p < 0.05). There were no significant differences between the P_e values of the digoxin-loaded nanoparticles, free digoxin in the presence of verapamil (dark gray bar) or digoxin-loaded nanoparticles in the presence of verapamil (light gray bar). Error bars indicate standard deviation (n = 3). PLGA: Poly(lactic-co-glycolic acid).