Nicotine hydrogen bitartrate salt

(+)-Methamphetamine HCl, (±)-methylphenidate HCl, and (±)-mecamylamine HCl were provided by the National Institute on Drug Abuse Drug Supply Program (Bethesda, MD). Bruce Blough (RTI) synthesized (±)-bupropion HCl, 2S,3S-hydroxybupropion HCl and 2R,3R-hydroxybupropion HCl, using previously described methods (Lukas et al., 2010 (link)). (−)-Nicotine hydrogen bitartrate salt (Sigma Aldrich, St. Louis, MO) was dissolved in sterile water and sodium hydroxide was added to the solution to reach a pH of approximately 5-7. Risperidone (Sigma Aldrich) was dissolved in 2% lactic acid (85% w/w; Sigma Aldrich) and sodium hydroxide was added to reach a pH of approximately 5-6. All other drugs, including varenicline tartrate (Sigma Aldrich) were dissolved in sterile water. All drug doses are expressed as the salt forms listed above, except for nicotine and Risperidone, which were expressed as the base. Nicotine doses were expressed as the free base by multiplying the bitartrate dose by 0.325 (Matta et al., 2007 (link)).

(−)-Cocaine HCl and (±)-mecamylamine HCl were provided by the National Institute on Drug Abuse Drug Supply Program (Bethesda, MD). (−)-Nicotine hydrogen bitartrate salt was purchased from Sigma Aldrich (St. Louis, MO) and sodium hydroxide was added to the solution to reach a pH of approximately 6. All solutions were passed through a 0.22 micron Millipore sterile filter (Millipore, Billerica, MA) before use. Drug doses were calculated and expressed using the salt forms listed above except for nicotine, which was calculated and expressed as the free base (Matta et al., 2007 (link)).