Stability of aqueous solutions of pirbuterol.
The hydrolytic degradation of pirbuterol was investigated under saturated oxygen conditions over a wide range of pH values and at different temperatures. Two of the five observed breakdown products were positively identified. The first-order decomposition rate appeared to depend on the rate constants of the four dissociated ionic species. The most stable region for the drug was pH 1-2, where the diprotonated molecule predominated; appropriate thermodynamic parameters were calculated.
D001993:Bronchodilator Agents / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D002855:Chromatography, Thin Layer; D004355:Drug Stability; D004983:Ethanolamines / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011725:Pyridines / Q000032:analysis*; D012996:Solutions / Q000032:analysis; D013696:Temperature; D013816:Thermodynamics
D001993:Bronchodilator Agents; D004983:Ethanolamines; D011725:Pyridines; D012996:Solutions; C009118:pirbuterol