Vacuum Decay vs. High Voltage Leak Detection: Choosing the Right CCIT Method

When it comes to ensuring the sterility and safety of pharmaceutical products, Container Closure Integrity Testing (CCIT) plays a central role. Two widely recognized methods - Vacuum Decay Testing and High Voltage Leak Detection (HVLD)- offer high sensitivity for detecting leaks. However, selecting the most suitable method depends on several factors, including container type, production environment, regulatory requirements, and overall inspection goals.

What is Advanced Vacuum Decay Testing?

Vacuum decay testing is a deterministic, non-destructive Container Closure Integrity Testing (CCIT) method that offers broad application flexibility and proven reliability across various pharmaceutical packaging formats. In this method, the air surrounding a sealed container is evacuated to a predefined vacuum level inside a hermetically sealed test chamber. If the container has a leak, internal air, gas or liquid escapes into the chamber, liquid will be vaporized, causing a measurable rise in pressure. The original vacuum decay technology is particularly well-suited for rigid containers such as vials, ampoules, and cartridges, especially for lyophilized or powdered products. With the advanced vacuum decay method (LFC method^® by WILCO) liquids can be inspected as well.

 

Key benefits of vacuum decay testing include:

• Non-destructive 100% inspection of each unit
• Quantitative and deterministic testing in compliance with USP<1207>
• Broad compatibility with different container types, sizes, and product formats
• No need for modified headspace or tracer gases
• Entire container system—including closure integrity—is tested

This makes vacuum decay a highly reliable solution for ensuring container integrity while maintaining production efficiency and regulatory compliance.

Key Features:

• Sensitivity: Detects leaks around 5 µm
• Regulatory Compliance: Endorsed by USP<1207> and EU GMP Annex 1
• Compatibility: Ideal for rigid containers like vials, ampoules, and cartridges
• Automation: Easily integrated into high-speed production lines
• Advantages: Non-destructive, deterministic, minimal operator intervention, scalable
• Limitations: Gas-flow required, products need be able to vaporize (alternative: Pressure Decay method)

What is High Voltage Leak Detection (HVLD)?

High Voltage Leak Detection is a deterministic, non-destructive CCIT method specifically suited for detecting leaks in liquid-filled parenteral containers. HVLD works by applying a high-voltage electrical potential across the container. If a leak path exists in the container wall or closure, the electrical current passes through the product, creating a measurable change in conductivity or voltage that indicates a breach in integrity.

Key Features:

• Regulatory Use: Aligned with USP<1207> for deterministic CCIT methods
• Compatibility: Suitable for liquid-filled glass or plastic containers (e.g., syringes, vials, cartridges)
• Advantages: Non-destructive, real-time results, effective with conductive solutions
• Limitations: Less suitable for lyophilized or powder-filled containers; product must be conductive

Sensitivity, Accuracy, and Throughput Comparison

Feature	Adv. Vacuum Decay Testing	High Voltage Leak Detection
Leak Size Sensitivity	~5µm	~2–5 µm
Product specification	All product types, such as liquid, lyo and powder Flammable liquids	Liquids with high conductivity
Filling level	Not relevant	Minimum fill level required
Accuracy & Repeatability	High, deterministic	High, deterministic
Cycle Time	Short, in seconds	Very short, real-time
Throughput Capability	High (in-line, automated)	High (in-line, automated)
Cost of Operation	Low maintenance, scalable	Moderate (electrical setup)
Sample Destructiveness	Non-destructive	Non-destructive
Operator Skill Level	Moderate	Moderate

 

 

Advantages of Vacuum Decay Over High Voltage Leak Detection

While HVLD provides rapid and effective testing for liquid products, vacuum decay stands out for its versatility and broader application range. Key advantages include:

1. Non-Destructive Testing Across Formats: Advanced Vacuum Decay accommodates both liquid and dry formulations, like lyophilized or powder-filled products.
2. No Product Conductivity Requirement: Vacuum decay does not rely on the product’s electrical properties, expanding its applicability.
3. Flammable liquids: In comparison to HVLD with it’s electric current, Advanced Vacuum decay can handle flammable products.
4. Low filling levels: Vacuum decay allows the inspection of products with any fill level
5. Cost-Effective Operations: Does not require high-voltage systems or special container handling setups.

These advantages make vacuum decay the method of choice for pharmaceutical companies that require flexibility, compliance, and proven performance across various container types and product states.