Vacuum Decay Cuts Waste

An operator places Mentor’s double tray into the PTI 225 and initiates testing with the push of a button.

Testing is David Derrick’s middle name. As QA lab manager for Mentor Corp. (Irving, TX), Derrick is responsible for ensuring the strength and integrity of his firm’s implant packaging. To do so, he has routinely employed an arsenal of tests. 

For instance, his lab has used dye-penetration and visual inspection tests for integrity testing and peel-strength tests for seal-strength testing. He has also employed various shipping tests. For routine monitoring during packaging, Derrick has performed peel-strength tests on samples from each lot. And the QA staff have repeated 100% visual inspection several times, both after sealing and after sterilization.

Despite all these tests, Derrick felt the need to supplement his testing program by taking advantage of recent technology improvements in nondestructive package testing.

So Derrick began researching other integrity tests, such as vacuum-decay and trace-gas testing. An Internet search led him to Packaging Technologies & Inspection (PTI; Tuckahoe, NY). About a year ago, he began evaluating PTI’s Model 225 vacuum-decay tester for trays with porous lids. In this case, Mentor’s breast implants are packaged in a lidded tray within a lidded tray, also called a double-tray system. The lid stock is coated Tyvek 1073B.

Tony Stauffer, president of PTI, explains that the PTI 225 is a standard machine for the medical device industry, consisting of a chamber, drawer, and fixtures customized for each package size. Once packages are placed in the drawer and the chamber is locked, a flexible bladder completely covers the porous lid so that no air can move in or out of the sealed package via the Tyvek. The sides and tray are exposed, however, so any channels or gaps in the seal between the tray and the lid and any holes in the tray itself will be exposed to the vacuum pressure. The chamber is then evacuated to a predetermined level and stabilized. Vacuum decay within the chamber is measured, including both absolute and pressure-differential vacuum. According to Stauffer, 100-µm channel leaks and 50-µm tray defects can be detected. 

Derrick says that he found vacuum decay and trace-gas sensing to be equivalent in sensitivity. He chose vacuum-decay testing because it is faster. “It is also easier to calibrate because it is traceable to NIST,” he says. 

Stauffer points out that the PTI 225 is nondestructive, which he feels is appealing to firms like Mentor. “When you put several hundreds of dollars into each product and package, you cannot afford waste.”

During his evaluation of the PTI 225, Derrick decided that the system could supplement his current testing and perhaps replace other tests. For instance, Derrick plans to first use vacuum decay to supplement peel-strength testing during process control. He then hopes to use vacuum decay for routine sample testing for quality control.

Derrick also looks forward to the ASTM method for vacuum-decay testing, which at press time was scheduled for release and naming in October. “An ASTM method will give me more testing validity and reduce the time I spend on future validations,” he says.

Stauffer reports that his firm worked with Dana Guazzo, PhD, of RxPax LLC, Pharmaceutical Package Development Consultants, to prepare un biased data to support an ASTM method. “The test method is a big accomplishment,” Guazzo says. “It is nondestructive and requires no treatment or additives. It’s quick, and you can calibrate to a standard leak rate. And the test method can be expanded to any type of packaging, porous and nonporous, rigid or flexible.”

For more information, visit PTI’s Web site at www.ptiusa.com or contact Dana Guazzo at danaguazzo@aol.com.