Container Closure Integrity Testing (CCIT) is essential for confirming that pharmaceutical packaging protects products from contamination, moisture, and oxygen exposure. By detecting leaks or seal failures, CCIT helps maintain drug sterility and product stability throughout storage and distribution. Modern deterministic testing technologies provide accurate, repeatable results that replace subjective inspection methods. These advanced systems align with global regulatory expectations such as USP . Understanding the principles of CCIT allows pharmaceutical manufacturers to select appropriate testing techniques, strengthen quality control processes, and ensure that packaging systems perform reliably from development through commercial production.