The elastic nature of latex has traditionally enabled the development of low-pressure medical balloons. But as the industry explores the use of alternatives to the common allergen, it has struggled with finding materials that exhibit the necessary properties for use in these particular products. Addressing this rising industry need, Polyzen Inc. has developed a patented process that enables the construction of low-pressure medical balloons from polyurethane films.
"Latex has great elasticity, and if you have a small neck to a large body ratio for a balloon, latex does a great job," explains Rubin T. Shah, director, business development, at Polyzen. "But in the marketplace, there are a lot of folks with latex allergies. And a lot of these nonlatex materials just don't have the same properties and expansion characteristics [as latex]." Nonlatex low-pressure balloons, the company states, have proven to be further undesirable owing to limitations of the 2-D form.
Overcoming these material limitations for balloon applications, Polyzen has developed a process in which polyurethane films are thermoformed into the balloon's two halves and then welded together. This method, according to the company, yields low-pressure, 3-D balloons with a previously unattainable neck-to-body ratio.
Capable of producing balloons with pressures up to 5 psi, Polyzen's process produces typical low-pressure balloons featuring a 3- or 4-in. balloon resting atop a 3-mm neck, according to Shah. The process can, however, accommodate balloon sizes down to 0.2 in. These devices are offered with 1:5, 1:10, and 1:20 neck-to-body ratios as well as any variation within that range.
"This [neck-to-body ratio] would not be possible with blow molding or dip molding, for example," Shah says. "This is one of the most cost-efficient and easiest ways to do this. Cycle times are also low and you can scale this up quite easily."
Although the welding process does create a seam in the balloon, it is nearly invisible and remains unobtrusive, according to the company. "We've actually done some products where we even inverted the seam," Shah notes. "So, there's no irritation of tissue in patients." As a result, low-pressure polyurethane balloons produced using Polyzen's process are suited for use in gastroenterology and vascular devices, plastic surgery applications, and tissue expansion, as well as for catheters employed in drug-delivery applications.