a bioadhesive extruded single or multi - layered thin film , especially useful in intra - oral controlled - releasing delivery , having a water soluble or swellable polymer matrix bioadhesive layer which can adhere to a wet mucous surface and which bioadhesive layer consists essentially of 40 - 95 % by weight of a hydroxypropyl cellulose , 5 - 60 % of a homopolymer of ethylene oxide , 0 - 10 % of a water - insoluble polymer such as ethyl cellulose , propyl cellulose , polyethylene and polypropylene , and 2 - 10 % of a plasticizer , said film having incorporated therein a medicament , e . g ., anesthetics , analgesics , anticaries agents , anti - inflammatories , antihistamines , antibiotics , antibacterials , fungistats , etc .