Preformulation studies of atenolol in oral liquid dosage form. I. Effect of pH and temperature.

The stability of atenolol solutions was evaluated under accelerated isothermal degradation conditions at 90 degrees C. A specific and sensitive HPLC method was adopted to study the pH dependence of the stability. The maximum stability of atenolol was achieved at pH 4. The degradation of atenolol followed first-order kinetics at 90 degrees C, pH 4 with k value of 1.1.10(-3) hour-1.