The Medical Design Engineer’s Resource for Products & Technologies

MDTMAG.COM | APRIL/MAY 2015

Elegant Reagent Delivery in POC Diagnostics

INSIDE: 4 Design Considerations for Integrated Drug Delivery Systems

6 Mantras for Medical Device Manufacturers

Technology Takes On Cancer

4 Aspects of Packaging Design for the Mindful Engineer

Cover Story In Vitro Diagnostics

Elegant Delivery Solution for Reagents in POC Diagnostics By Blake S. Perkins, Exec. Director, Diagnostic Business Development, J-Pac Medical

T he continuing growth of point-of-care (POC) in vitro diagnostic (IVD) testing is supported by

technology improvements and the recognition that rapid test results offer economic and patient outcome bene-fits. Frangible seal technology offers an elegant and cost-effective solution for dispensing unit-of-use reagents for POC medical diagnostic devices.

Frangible sealed reservoirs use differ-ential weld strengths that are designed to fail under specific pressures, allowing for a unit-of-use measure to be precisely delivered to a target well or reaction zone. By incorporating frangible seal technology into on-board reagent blisters of POC devices, the device manufacturer is able to better control performance variability, reduce overall manufacturing and disposal costs, and simplify the user experience.

Incorporating Blister Technology into POC DevicesAn increasing number of POC device manufacturers are incorporating burst and frangible seal reagent blister reservoirs into lateral flow and lab-on-a-chip/card formats, as they are easily integrated and reliably dispense unit-of-measure volumes of reagent precisely to the targeted area. This is replacing the use of conventional eyedropper and bottled reagents by the technician to deliver an approximate vol-ume to a capture zone, thereby eliminating the opportunity for sampling errors.

It is important that frangible seal manufacturers consider the specific require-ments of every custom blister reservoir and design a blister solution that considers material compatibility, burst characteristics, reagent volume delivered, and long-term storage requirements. There are several

different types of materials that can be used for reagent blisters and generally can be described as specialized foils and lami-nates used for cold- and thermo-formed packaging. These materials have various thicknesses and seal strengths that can be used for pierced or burst/push-through, peelable, and hybrid peel-push barriers.

Depending on the form factor and release requirements, a wide range of ma-terials can be processed to create “frangi-ble” blister seal reservoirs with differential weld strengths designed and engineered to either be permanent or break, distort, or yield on contact actuation or fail under a specific pressure. These weld strengths on the reservoir seals are a function of the material properties and applying unique welding processes that are combinations of pressure, temperature, and time to meet the seal specification.

An understanding of these special-ized material properties and processing allows the blister fabricator to “dial-in” the specific burst strength needed for activation – though not fragile enough to rupture pre-maturely due to routine handling, assembly, or shipping activities. Demonstrating this flexibility, a single blister design was created with a frequently used foil material set and then sealed using different processing parameters. The sealed blisters were actuated and measured for the force required to release the contents (Chart).

This process-ing control of the seal strength

allows the medical device manufacturer to have confidence that the reservoirs will release their contents under defined and controlled conditions. Additional levels of seal strength (lbf — pounds force) can be developed and optimized using different material sets and processing conditions, thereby expanding the selectivity of the activation range of the blisters.

Cost ConsiderationsThere are tangible reductions in overall manufacturing and end-user costs by in-corporating frangible seal reagent blisters into POC devices.• It reduces the number and cost of sepa-

rate reagent bottles and applicators, and

IVD device representation with reagent blisters

Chart: Three different populations of burst blisters were created reproducibly for different burst values by making adjustments in the processing parameters.

associated costs of filling, packaging, and labeling.

• The reagent blister stores and delivers just the right amount of reagent needed for the determination, so ex-cess reagent is not required. The liquid volume for single dose reagents can range from 30 to 5,000 μl.

• The blister form factors are compat-ible with various reagents, powders, beads, liquids, and solvents, thereby reducing the number of materials needed for the test kit.

• Larger blister cards with multiple reagents (multiplexing) can be used to reduce the number of overall compo-nents and assembly steps.

• The reagents can be lot-matched on the device, removing potential confu-sion and misuse by the end user.

• Reservoirs are lightweight and dispos-able components when integrated into the device, reducing waste.

• The materials used have low vapor barrier transmission rates, resulting in greater stability and longer shelf life (>2 years), in some cases eliminating the need and cost of desiccants.Additionally, blisters are easily

customized and integrated into many existing platforms; this helps manu-facturers create new offerings without drastic changes in the product line. Burst pressure and pin-point release of the reagent from the blister reservoirs can be designed into the blister shape for either manual or mechanical actuation. Accu-rate filling and dispensing by design — in single or multiplex formats — allows tests to be consistent and reproducible.

ConclusionThe application of frangible seal tech-nology to reagent blisters enables greater control over unit-of-measure release of testing reagents and provides improved

performance characteristics and practical implications when compared to current drop bottle formats.

These features translate into benefits for the POC device manufacturer by low-ering manufacturing and packaging costs, increasing reagent stability, and providing a smaller disposable footprint that offers easy, accurate, and precise fluid transfer.

In turn, by integrating frangible seal technology into on-board reagent deliv-ery, POC tests can lower cost, shorten time-to-result, and increase reliability and stability. Frangible sealed reagent blisters show the promise of making POC devices more affordable and repro-ducible, with improved patient outcomes and high confidence in the test results.

Frangible seal technology simplifies point-of-care diagnostics testing by enabling the controlled release of testing reagents.

Cover Story In Vitro Diagnostics

For more, visit www.j-pacmedical.com.

Posted from Medical Design Technology, April/May 2015. Copyright © Advantage Business Media. All rights reserved.#C37920 Managed by The YGS Group, 800.290.5460. For more information visit www.theYGSgroup.com/content.