How to measure mucoadhesion/bioadhesion

Mucoadhesion and bioadhesion refer to the ability of a drug delivery system (usually a polymer or gel) to adhere to biological surfaces, allowing for targeted and prolonged drug release. These properties are critical in the fields of pharmaceuticals, medical devices, and biotechnology, where localised or controlled drug delivery and prolonged contact with biological tissues are essential for effective treatment.

Mucoadhesion specifically describes adhesion to mucosal surfaces such as the gastrointestinal tract, oral cavity, nasal passages, or vaginal and ocular tissues. As many infections originate in mucous membranes, mucoadhesive drug delivery systems enhance treatment efficacy and protect drugs from harsh internal environments. These systems are used for treating conditions in the mouth, rectum, vagina, and nose, and have been investigated for treating stomach ulcers and cancer. Bioadhesion is a broader term referring to adhesion to any biological tissue, such as skin, tissues, or cells. Bioadhesive materials are used in wound healing, tissue engineering, and drug delivery systems.

A Texture Analyser is an established tool for measuring muco/bioadhesion bond strength, a crucial factor in developing effective pharmaceutical dosage forms.

Mucoadhesion and bioadhesion testing using a Texture Analyser plays a critical role in evaluating adhesive properties for pharmaceuticals, biotechnology, and medical devices. Below are key applications:

• Mucoadhesive gel strength testing: Evaluating the adhesive strength of pharmaceutical gels designed to adhere to mucosal surfaces by measuring the force required to detach the gel from a mucosal membrane model.
• Dental adhesive bioadhesion assessment: Assessing the bioadhesion of dental adhesives used in restorative materials by measuring the force needed to detach the adhesive from a tooth-like surface.
• Ocular mucoadhesive strength analysis: Testing the adhesive strength of ophthalmic drug delivery systems by measuring the force required to detach an ocular patch from an eye model surface.
• Transdermal patch bioadhesion testing: Measuring the bioadhesive strength of transdermal patches designed for drug delivery by assessing the force needed to remove the patch from a skin-like surface.
• Bioadhesive film evaluation: Testing the adhesion strength of bioadhesive films or patches used in wound care by measuring the force required to detach the film from a skin-like surface.
• Intraoral mucoadhesive device testing: Evaluating the adhesive strength of intraoral devices like buccal tablets or patches by measuring the force required to detach them from a buccal mucosa model.
• Nasal drug delivery bioadhesion analysis: Assessing the adhesive strength of nasal drug formulations by measuring the force required to detach a nasal spray formulation from a nasal mucosa model.
• Gastrointestinal mucoadhesion testing: Measuring the adhesive properties of gastrointestinal drug delivery systems by assessing the force needed to detach a tablet or patch from a gastrointestinal mucosa model.
• Vaginal bioadhesive product evaluation: Testing the adhesive strength of vaginal drug delivery products like gels, creams, or rings by measuring the force required to detach them from a vaginal mucosa model.

In these examples, a Texture Analyser is used to apply controlled forces/distances to adhesive materials, measuring the detachment strength from biological surfaces. These measurements are vital for developing effective drug delivery systems, medical devices, and formulations designed to adhere to biological tissues for extended periods.

In a typical mucoadhesion/bioadhesion test, a mucosal substrate, such as porcine tissue, is clamped to reveal an exposed region.  The tissue is immersed in a controlled temperature liquid simulating the human gastric conditions. A probe containing the tablet, powder or gelled sample is brought down onto the mucosae for a chosen time and holding a chosen force after which the force to detach the sample from the mucosae is measured.

• Contact time: The duration of contact between the bioadhesive material and the biological surface significantly influences the strength of adhesion, as longer contact times generally allow for stronger bond formation.
• Applied force: The initial force applied to bring the bioadhesive material in contact with the biological surface affects the extent of interaction and subsequent adhesion strength.
• Detachment speed: The rate at which the bioadhesive material is separated from the biological surface during testing can influence the measured adhesion strength, with slower speeds often providing more precise measurements.
• Amount of test material: The quantity of bioadhesive material used in the test can affect the contact area and distribution of forces, impacting the measured adhesion strength.
• Choice of substrate: Choose appropriate substrates that mimic target application sites.

The Stable Micro Systems Texture Analyser stands out in optimising mucoadhesion/bioadhesion measurements through its comprehensive approach and specialised features. Equipped with dedicated tools like the Mucoadhesion Test Rig and Gel Mucoadhesion Probe, it precisely quantifies adhesive properties of various pharmaceutical dosage forms, including solids, semi-solids, and in-situ gelling systems.

The Texture Analyser provides accurate measurements of adhesiveness, debonding distance, and work of adhesion, while its Exponent Connect software captures detailed force-distance-time profiles for in-depth analysis using a unique Adhesive Test sequence. Customisable test settings ensure adaptability to unique sample requirements, and the system's popularity as an industry standard makes it widely accepted in pharmaceutical research.

Backed by Stable Micro Systems' expertise in method development and data interpretation, this makes it the ideal choice for researchers and manufacturers in the pharmaceutical and biomedical fields seeking to refine formulations and optimise mucoadhesion/bioadhesion properties.