I'm a bit confused about how polar molecules can be insoluble in water. Polar means they have a permanent dipole so I would have assumed that they would solvate water. An example of a polar insoluble compound is pyrantel embonate. Its used to treat hookworm and pinworm infections in the GI tract. Its low water solubility and high polarity mean it can't travel to other areas or bypass membranes very well and consequently, it gets localized to its site of action. Again though, I don't understand how a polar molecule can be insoluble in water.