Bioimpedance Spectroscopy Improves Insulin Absorption Measurement Method: A Feasibility In-Vivo Study Based on Saline

A feasibility of a method based on impedance spectroscopy and equivalent circuit approach to assess insulin bioavailability is realized in-vivo by exploiting a vehicle as insulin emulator. The vehicle bioavailability is indirectly assessed by measuring the local impedance variation due to the drug disappearance from the injection volume. An experimental campaign was carried out on a healthy subject to acquire bioimpedance spectra in the frequency range of [1-100] kHz during controlled administration of vehicle. A modified Tregear’s model is proposed to model the investigated phenomena. In particular, a linear relationship between the resistor used for modelling the hypodermis and the amount of vehicle injected was found. The method based on equivalent circuit exhibited an improvement in sensitivity (70 %) with respect to the approach based on percentage variation of impedance magnitude.