muco adhesion

8/18/2019 Muco Adhesion

1/8

Mucoadhesion


2/8

Defnition

•Bioadhesion is defned as an ability o material tadhere to biological tissue or an extended periotime.

• In the case o polymer attached to the mucin lthe term mucoadhesion is used.

• Mucoadhesive dosage orms may be designed toprolong retention at the site o application, provcontrolled rate o drug release or improved theroutcome.


3/8

Ideal characteristics omucoadhesive approach•

Rapid adherence to the mucosal layer without achange in the physical property o the delivery m

• Minimum intererence to the release o the activ

• Biodegradable without producing any toxic bypr

• nhance the penetration o the active agent


4/8

!dvantages o mucoadhesion

•

Increased residence time leading to enhancedadsorption

• Improved intimacy o contact with various biologmembranes

• Improved bioavailability through the protection obioactive molecules rom physical and chemicaldegradation

• "argeting and locali#ation o a release device at specifc site


5/8

Disadvantages o mucoadhesio

•

Medication that administered orally do not enterblood stream immediately ater passage throughmucosa

• $ertain drugs undergo drug destruction whenadministered orally and a%ect liver metabolism

•&ral ingestion results in more exposure o a drug'I" and destruct normal micro(ora resulting in dand overgrowing dangerous organisms

• "he absorption is adversely a%ected by the presood


6/8

)actors in(uencing the strengththe mucoadhesionMolecular weight and

crosslinking of the polymer

"he adhesive strength increases by increasing the Mr andcrosslin*ing density so polymer does not lose its (exibilityelasticity.

The spatialconguration of the

polymer

In the case o a linear polymer, bioadhesion is improved bthe Mr. In the case o a nonlinear polymer, it needs a signincrease o Mr.

Concentration +eed optimum concentration, not necessarily the highest

$hain (exibility

Increased to enable interpenetration o polymer chains thmucus layer.

Hydration capability I the degree o hydration is high, the adhesive propertiespolymer are lost due to the ormation o slippery, nonadhmucilage near the interace.

Functional groups -olymers containing hydroxyl, carboxyl, and some aminessulates are potentially good bioadhesives.


7/8

Main stages in mucoadhesion

•

Contact stage "he mucoadhesive polymersmust spread over the mucuslayer to initiate closecontact and to increase thesurace area o contact.

• Consolidation stage

"he adhesive oints must bestrengthened andconsolidated, leading to aprolonged adhesion.

/ource0 www.scielo.b


8/8

muco adhesion

Documents