title: Acido-basic properties of proton pump inhibitors in aqueous solutions.
abstract: The pharmacological characteristics of proton pump inhibitors are related to their protolytic behavior estimated by their pK(a) values. Lansoprazole is a potent anti-acid drug from this group. Because of its poor stability a rapid spectrophotometric method was developed for the determination of its pK(a) values. Three pK(a) values were obtained: an acidic pK(a1) = 8.84 and two basic, pK(a2) = 4.15 and pK(a3) = 1.33. These pK(a) values were discussed from the point of lansoprazole structure and instability with the aim of locating basic and acidic moieties in the molecule of proton pump inhibitors. They were also compared with experimentally determined pK(a) values from the literature and with some pK(a) values calculated by different programs.
authors: University of Ljubljana, Faculty of Pharmacy, Ljubljana, Slovenia. albin.kristl@ffa.uni-lj.si
authors: Albin
authors: A
authors: Kristl
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000737:chemistry*; D000897:Anti-Ulcer Agents / Q000737:chemistry*; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D064747:Lansoprazole; D054328:Proton Pump Inhibitors / Q000737:chemistry*; D012996:Solutions; D013053:Spectrophotometry / Q000379:methods*
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D054328:Proton Pump Inhibitors; D012996:Solutions; D064747:Lansoprazole