Considering solubility characteristics of a drug in the stomach (i.e., pH range of 1 to 3) are pretty much useless from a drug’s absorption perspective. Even if a drug gets dissolved in the stomach, it will be precipitated out in the intestine if it has lower solubility at a higher pH.
For absorption purposes, a drug must dissolve, not necessarily completely but in some quantity, in the intestine where pH ranges from 4.5 to 7. Drugs get absorbed in steps in the intestine by a continuous extraction process; thus, the complete dissolution of drugs at any given time (so-called “sink condition”) is unnecessary.
Moreover, dissolution characteristics are not usually determined for a drug – dissolution tests are conducted to evaluate products. The choice of medium is linked to the physiological environment of the GI tract, not to the drugs or products. Please pay attention to the principles of science and the laws of nature. For further detail, please follow the link (link).