In vitro biodistribution of silver nanoparticles in isolated perfused porcine skin flaps

Nanomaterials increasingly are playing a role in society for uses ranging from biomedicine to microelectronics; however, pharmacokinetic studies, which will be necessary for human health risk assessments, are limited. Currently the most widely used nanoparticle in consumer products is silver (Ag). The objective of the present study was to quantify the local biodistribution of two types of Ag nanoparticles, Ag-citrate and Ag-silica, in the isolated perfused porcine skin flap (IPPSF). IPPSFs were perfused for 4 h with 0.84 µg ml(-1) Ag-citrate or 0.48 µg ml(-1) Ag-silica followed by a 4-h perfusion with media only during a washout phase. Arterial and venous concentrations of Ag were measured in the media by inductively coupled plasma optical emission spectrometry (ICP-OES). Venous concentrations of Ag for both types of nanoparticles were best fit with a two compartment model. The normalized volumes of distribution estimated from the noncompartmental analysis of the venous concentrations indicated distribution of Ag greater than the vascular space; however, because total Ag was measured, the extravascular distribution could be attributed to diffusion of Ag ions. The estimated clearance for both types of Ag nanoparticles was 1 ml min(-1) , which was equal to the flap perfusion rate, indicating no detectable elimination of Ag from the system. Four hours after infusion of the Ag nanoparticles, the recovery of Ag in the venous effluent was 90 ± 5.0% and 87 ± 22% of the infused Ag for Ag-citrate and Ag-silica, respectively.