Development of transdermal system containing nicotine by using sustained release dosage design

This study was carried out to develop a membrane-controlled transdermal formulation (TF) of nicotine by using sustained release dosage design (SRDD). TFs were prepared with polyethylene membrane as a rate-controlling barrier; a carbomer was used as the gel reservoir with or without propylene glycol (PG). The in vitro target flux (0.0535 mg cm^–2 h^–1) was calculated according to SRDD calculations. Nicotine permeation through the membrane with or without transfer adhesive was also studied using diffusion cells. Nicotine permeated through membrane (without adhesive) with a flux of 0.0555 mg cm^–2 h^–1 and this value was similar to that of the in vitro target flux. The release from the TFs and from a commercial product (Nicotinell, 52.5 mg 30 cm^–2) was studied using the FDA paddle method. The nicotine amount was increased from 22.7 to 56.5 mg in gel reservoir, and a plateau was reached beyond 45.4 mg of drug; the system attained the maximum thermodynamic activity with 56.5 mg of nicotine. The release rate from TFs (without adhesive layer) containing PG in the reservoir was very similar to the target release rate (1.07 mg h^–1). The fluxes of nicotine from Nicotinell and TF containing 45.4 mg of nicotine were close to the in vitro target release rate.