The dehydration theory explains why mucoadhesion can arise rapidly. When two gels capable of rapid gelation in an aqueous environment are brought into contact, movement occurs between the two gels until a state of equilibrium is reached. Gels associated with a strong affinity for water will have high osmotic pressures and large swelling forces. The difference in osmotic pressure when these gels contact mucus gels will draw water into the formulation and quickly dehydrate the mucus gel, forcing intermixing and consolidation until equilibrium results.
This mixture of formulation and mucus can increase contact time with the mucous membrane, leading to the consolidation of the adhesive bond. However, the dehydration theory does not apply to solid formulations or highly hydrated forms.