1. A method for the direct transmucosal delivery of fentanyl or a fentanyl derivative as an anesthetic to a subject’s body, comprising applying a biodegradable drug delivery device to the subject’s oral mucosa, said delivery device containing fentanyl or a fentanyl derivative in a mucosalbase polymer diffusion medium characterized by a value a pH of about 7.25, and a barrier medium located relative to the mucoadhesive polymer diffusion medium Kim manner that upon application of said means of delivery to a mucosal surface creates a unidirectional gradient, and achieved the delivery of fentanyl or a fentanyl derivative subekta.2 organism. The method according to claim 1, wherein said delivery vehicle is characterized by direct buccal absorption of fentanyl or a derivative thereof at a level of at least 50% and an absolute bioavailability of fentanyl or a fentanyl derivative at a level of at least about 70%. The method of claim 1, wherein an effective amount of fentanyl or a fentanyl derivative is delivered to the subject in less than about 30 minutes. The method of claim 1, wherein the delivery is to alleviate chronic pain in a subject. The method of claim 1, wherein the delivery is to alleviate acute pain in a subject. The method of claim 1, wherein the delivery is to alleviate sudden uncontrolled pain in a subject. A method according to any one of claims 1 to 6, in which fentanyl is available in an amount of about 800 mcg. The method according to any one of claims 1 to 6, in which the specified delivery vehicle further1. Способ прямой трансмукозальной доставки фентанила или производного фентанила в качестве обезболивающего средства в организм субъекта, включающий наложение на слизистую поверхность ротовой полости субъекта биоразлагаемого средства доставки лекарства, при этом указанное средство доставки содержит фентанил или производное фентанила в буферной мукоадгезивной полимерной диффузионной среде, характеризующейся значением pH приблизительно 7,25, и барьерную с
