In the early 1980s, academic research groups pioneered the concept of mucoadhesion as a new strategy in order to improve the therapeutic effect of various drugs. Mucoadhesive polymers are able to adhere to the mucus gel layer which covers various tissues of the body. These mucoadhesive properties are in many cases advantageous, rendering such polymers interesting tools for various pharmaceutical reasons:

1. Mediated by mucoadhesive polymers, the residence time of dosage forms on the mucosa can be prolonged, which allows a sustained drug release at a given target site in order to maximize the therapeutic effect. Robinson and Bologna, for instance, have reported that a polycarbophil gel is capable of remaining on the vaginal tissue for 3-4 days and thus provides an excellent vehicle for the delivery of drugs such as progesterone and nonoxynol-9 [1].