In vitro characteristics of nicotine microspheres for transnasal delivery

A new transnasal formulation containing nicotine was developed and characterized. Sephadex(R) G25 and G50, crosslinked dextran microspheres, were loaded with nicotine base (NB) and nicotine hydrogenotartrate (NHT). Their high swelling capacity, which is believed to enhance the bioavailability of nicotine by acting on the nasal mucosa, was not altered by the loading process. The in vitro kinetics were measured by the means of a special diffusion chamber which mimics the hydration conditions of the nasal cavity. 90% of the nicotine were released in a time similar to the nasal residence time (15 min). The delivery from a regular nasal device is described and related to the porosity of the microspheres.