Software that models the laws of physics is usually used by theoretical physicists. But a multi-physics program based on “1st principles” can be used in real-world applications, as evidenced by a problem that cropped up for Eli Lilly (NYSE:LLY) while developing needle-based drug-delivery systems.

Bernard McGarvey, a senior engineering advisor for the US pharma giant, said the software helped the Lilly team deal with an issue involving the needles used in delivery devices for biologic products. The Indianapolis, Ind.-based team develops drug delivery devices such as the KwikPen insulin delivery device and the newer Trulicity delivery device.

The desire to increase product concentration, and therefore viscosity, designs for similar needle based delivery devices in the future will need to confront a dilemma: The devices’ needles needed to be small enough to be comfortable for patients but large enough that the force required to push the medication through the needle wouldn’t cause a delivery problem.

“As is the case with a lot of engineering problems, you have two things that are perfectly opposed to each other,” McGarvey explained at COMSOL’s annual conference last week in Boston. “This is a real problem for the industry.”

A needle vendor presented them with an elegant solution: A tapered needle that might cut the required delivery force significantly while not increasing the pain from the injection for the patient.

Using COMSOL’s multiphysics modeling software, the Lilly team modeled the proposed tapered design using variables based on fundamental physical properties, including the expected manufacturing variability of such tapered needles.

“I define first principles as the fundamental causal physical relationships that constrain the behavioral process of the system,” McGarvey said.

The software helped the team show that a tapered needle design could cut the required delivery force by up to 40%-50%.

“Sometimes what we find is the most effective examples sometimes are actually the simplest,” McGarvey said.

Using a software model early on can provide a solid foundation of understanding on which to build a device, he noted. The company now has a solution to help reduce the required device delivery force.

“If you’re trying to get some people enthusiastic about spending money, spending their time, stuff like that, if you can really explain to them why this is the right way to go and not some other way, that’s very advantageous,” McGarvey said. “That means that we have a system that we understand. That gives you confidence to go out and make these things.”