Article in the LABO magazine: Using microfluidics to assess injectability & syringeability
Injectable medications are used to treat many different illnesses. There are various types of injection: intramuscular, subcutaneous, intravenous, intradermal and others. Different needle gauges and syringe barrels can be chosen depending on the type of injection and this has a direct impact on the shear rate applied to the injectable liquid and can therefore impact the viscosity. The shear rate applied when injecting is high because of the small gap of the needle which means it has a high impact on the viscosity. Therefore, it is essential to carefully control the viscosity of the injectables by testing them at high shear to mimic the injecting conditions.
Effective drug delivery is a subject of research in thousands of groups all over the world. One way in which drugs can be delivered is by using liposomes. Liposomes are spherical vesicles that have one or more lipid bilayers, the spherical form allows active molecules to be trapped inside and these molecules are then released into the target cells when the lipid bilayer of the liposome fuses with the bilayer of the cell membrane. Drug delivery is the main use of liposomes however, there are other areas where they are used such as: dietary supplements, pesticides, dyes for textiles and cosmetics.
Analyzing injectable formulations at high shear is essential to understand their behavior when injected. The proposed methodology provides a mapping of different injection configurations (depending on the type of injection) allowing to monitor the syringeability, considering the injectable formulation viscosity and the injection pain limits. The FluidicamRHEO can be used to analyze injectables quickly and easily over a wide range of shear rates from 100 to 180,000s-1 and with extreme precision.
The FluidicamRHEO is a powerful tool for the comparison of injectable liposomes with as little as 1 ml needed to plot a flow curve. The high sensitivity when measuring low viscosity samples means very small differences can be observed and the impact of the temperature on the liposomes can also be studied in minutes.