Physicochemical properties of amphoteric beta-lactam antibiotics I: Stability, solubility, and dissolution behavior of amino penicillins as a function of pH.
The degradation rate, solubility, and dissolution rate of amino penicillins, amoxicillin, ampicillin, epicillin, and cyclacillin, were determined quantitatively as a function of pH. In the pH range studied, 0.30-10.50, the degradation of amoxicillin and epicillin followed pseudo-first-order kinetics to give the same type of pH-rate profiles as those of ampicillin and cyclacillin. Cyclacillin anhydrate was the most soluble, followed in order by ampicillin anhydrate, ampicillin trihydrate, amoxicillin trihydrate, and epicillin anhydrate. These pH-solubility profiles showed showed U-shaped curves. The dissolution rate constants from the rotating disk were analyzed by the simultaneous chemical reaction and diffusion models. Their relative bioavailability after a single oral administration was assessed from their physicochemical properties determined in vitro.
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D009994:Osmolar Concentration; D010406:Penicillins; D012995:Solubility; D013501:Surface-Active Agents; D013696:Temperature
D010406:Penicillins; D013501:Surface-Active Agents