Solubility and partitioning. VII: Solubility of barbiturates in water

The solubility equation of Yalkowsky was used to estimate the aqueous solubility of 33 barbiturates in the temperature range of 5 to 45 degrees C. The equation was extended by adding a term which accounts for the effect of pH on the solubility of the drug. The extended equation is successful in estimating the aqueous solubility of this series of drugs under different conditions of temperature and pH. The results indicate that the extended equation can be used to estimate the aqueous solubility of nonelectrolytes as well as weak electrolytes.