Butamben/Ketamine

This is a multi-center, randomized, controlled, partially blinded study to assess the pharmacokinetics and comparative bioavailability of nicotine from two variants of NP2 (4 and 6 mg) in comparison with Loz-4mg and Gum-4mg in adult cigarette smokers. The subjects will be blinded to the randomized sequence and will be blinded to the variants of NP2 they will receive. The study will be conducted with 4 periods and 4 sequences in a Williams design (crossover).