High Voltage Leak Detection (HVLD) method exploits the electrical conductivity of a liquid product that is packaged in a container made of non-conductive material.
A high-frequency voltage potential is applied to the container by means of suitable electrodes and the discharge current is measured by the system.
If cracks or pinholes are present on the container surface the discharge current ﬂows into the container through the leaking path.
Pass/Fail criteria is established during equipment validation.
- The detection principle of HVLD is basically different from methods which rely on mass transfer and mass exchange through the defects in the container.
- This difference provides HVLD with an exclusive advantage to overcome drug products clogging issues.
- Clogged defects, although they may prevent mass transfer, can allow electrical current to flow through and thus enable consistent defect detection by the HVLD system.
- A further advantage is that highly concentrated drug substances do not represent a limitation due to viscosity and density that could lead to a more difficult transfer through a leaking path.