Adhesion Strength Testing of Bioadhesives

Bioadhesive polymers are synthetic or natural polymers that are incorporated into pharmaceutical formulations used in drug delivery systems. They allow absorption of drugs to biological substrates such as tissues or mucous membranes. In a bioadhesive drug delivery system, the drug carriers remain in close contact with the absorption surface, releasing the drug to the targeted location. This more targeted approach to drug delivery achieves a better therapeutic effect compared to oral drug admission.

The bioadhesive strength, which is the maximum adhesion force between the bioadhesive and the targeted substrate, must be strong enough to ensure that an effective concentration of drug is maintained at the specific site for a sufficient time period. This is why testing is critical in the development of bioadhesives.

In this test, the bioadhesive layer was applied to the flat surface of the upper specimen holder and fixed to the movable crosshead of our 5948 MicroTester configured with a 10N loadcell. It was then brought into contact with the targeted substrate, attached to the lower specimen holder. A preload of 5N was applied and maintained for 6 seconds to allow for the formation of the adhesion bonds. After the holding period, the crosshead was moved upward at a constant speed to separate the two surfaces and the maximum adhesion force was recorded. The test control and calculation of results were performed by Bluehill 3 software. The entire test was performed under physiological conditions using a custom Temperature Controlled Bath. This bath allows accurate control of the bath temperature at 37°C ± 1°C.

We would like to thank Nanyang Technological University, School of Material Science and Engineering – Biomaterial group, for contributing to the above information.